I turned off my game audio and controller vibrations. Both were distracting me and messing up my internal clock, but you should do whatever you need to get a good tempo; so pull up a song you can vibe to if that's what it takes and get as comfy as possible.

For all three challenges, try to stay within the center of the screen as much as possible. You want the maximum amount of usable space regardless of the event.

Keep your eyes on Hornet herself as much as possible. Your brain will figure out the incoming obstacles through your periphery, but you need to track where Hornet is at all times.

To beat Seth's scores you're going to have to not pay any attention to the flea count. Looking at it at all will just distract you or make you anxious and perform worse. Focus solely on the main objective of each game respectively:
*Juggling - Just keep hitting to the beat and only pay attention to the fleas that are already in the arena. The freshly spawned ones aren't important until they make their first jump in.
*Dodge - Worry only about staying on platforms, don't even think about dodging freshly spawned fleas.
*Bounce - The literal only thing that matters is keeping your airtime up. Once you come to terms with letting multiple fleas go by without bouncing on them you'll easily breeze through it.

This one is definitely the toughest until you understand a few nuances about the way the fleas fall and how Hornet's attack hitboxes work.
I used Wanderer's Crest to beat it because I was most comfortable with it and the attack speed was relevant. But I've come close enough with Beast and Shaman that I think both are viable options. I don't recommend Architect, but I suspect the other 3 can work if you're really used to their attacks. Make sure you're using the Longclaw no matter which you choose.

*Make sure all your hits against each wave of fleas are in the same direction, you may need to dash and fast turn to ensure it, but facing opposite directions on hits is what causes the wave to split up which will make it impossible to catch all of them.

*The steel fleas are unfortunately absurdly annoying at throwing your tempo off, I couldn't figure out any trick with them besides just practicing enough to learn their timings. With the gold ones later on just remember that they jump backwards a little after the 3rd hit.

*The fleas' falling momentum is based on their height. Knocking them upward causes them to fall faster after they hit the apex. This is the biggest misnomer about this minigame: DO NOT ATTACK UP OR JUMP ATTACK: IT WILL MAKE IT HARDER.

*Simply do normal attacks in the direction you're facing as the fleas descend. Your normal attack hitbox has a shockingly large vertical arc to it. It goes way past where the particle indicator is and you'll learn its range very quickly by doing this repeatedly. Its horizontal tip is also much longer than you'd think so it can catch fleas that fall off the stage ends with ease.

*While Hornet can't hit behind her with a normal attack, she can hit something almost exactly parallel vertically to her (I think it needs to be at least one pixel forward from her center), and hitting the fleas with normals as close to her center as possible will cause them to bounce straight up much more slowly than an up attack would.

*If you have a mod to show hurtboxes and hitboxes that would probably trivialize this. But I put some images together with an approximation of Longclaw enhanced Wanderer's Crest to show off the absurd invisible range Hornet can catch things with.

This minigame is #$%&ing stupid. Complete RNG fest, Team Cherry absolutely needs to rework it. One of the most miserable parts of Silksong so if you're raging at it don't worry; it's justified.

I can give a bunch of very minor tips but ultimately the only thing that will get you there is slamming your head against it repeatedly until you get a good seed where a giant flea doesn't knock a platform down in a way that automatically ends the run for you because it's physically impossible to stay in the air long enough for the new one to spawn (or the awful scenario of a brew empowered flea spawning simultaneously with another flea on the same trajectory).

*Getting hit while you're on a platform actually isn't a big deal. Hornet can jump and ledge grab back 90% of the time. The issue is if you're bumped while in the air or in free fall from a first hit; then it's almost guaranteed game over.

*Don't forget to use your downward dash for fast falling.

*The vertical downward fleas can't hit you if you're on the edges of the platform (Sometimes they'll lean slightly towards a side; just position on the opposite one and stand there).

*If you do get knocked off and are guaranteed not to be able to reach the platform again, hold float as long as possible and spam harpoon to get 1-3 extra fleas as you fall to your end.

*When Vog jumps up to throw the spear she will always aim at where you were right as she does the jump up. Make small movements or jumps to guarantee the dodge.

*Harpoon to get horizontal momentum back to platform if you're knocked off straight left or right. You can also use it on a flea while you're falling to reset your jump.

*When a giant flea spawns, wait to jump until the last possible moment before it destroys the platform. Hold jump, double jump, then float as long as possible for the best chance of a platform resetting by the time you make it down. If it spawns while you're on a super low platform you'll have to nail bounce off it for enough height to stall for the platform.

*Standing still for as long as possible is the best advice I can give in terms of gitting gud. Minimize your air time so you still have jumps to use if you do get bumped.

*If you're really crazy, then you can keep trying for a seed that lets you air bounce almost indefinitely above the top row (just make sure you're over a platform just in case you have to fall). I highly recommend against making this your main strategy, but it is technically the safest option if the fleas spawn in an arrangement that allows it. This does become more viable after you get to 70+ because of the sheer number of fleas that spawn.
Do keep in mind that you can't bounce off the top row spawns until they've already started coming down a bit.

*Remember that Hornet's hurtbox does not extend to her horns. While the fleas (thankfully) have extremely precise body hitboxes. If you don't need to jump because only Hornet's horns would be grazed then that's a great scenario to help keep your movements minimal.
A good example below:

Probably the easiest of the three for most people, especially if you pogo enemies liberally throughout your playthrough. Since this one is the least RNG based the tips should help more, but there's also not a lot of them since the majority of it is getting your reflexes trained and understanding the tempo.

*Don't feel like you have to bounce off every flea that runs by. Staying airborne as long as possible should be your only goal, you'll eventually top Seth's score just by being up there as long as possible; trying to rush it is a guaranteed way to drop.

*Only use your double jump when absolutely necessary and keep floating to an absolute minimum. Each bounce will reset your extra jump.

*Use your harpoon if you need the horizontal momentum or to save yourself by snagging a flea. It will also reset your second jump.

*Do your best to stay center screen; no matter which direction the fleas come from they'll cross up there so it allows you the most freedom to select a bounce in case you miss one.

*Unlike with juggling, I HIGHLY recommend Shaman's crest + Longclaw for this one. The hitbox area it covers is ridiculous and as long as you're used to the tempo there shouldn't be any issues staying airborne.