Deadly trap combos are remembered by players, who then build their own bases around them
Here are some notable ones and how to beat them:

Look at all the blue parts you have, those could easily be grenades and bubble shields. Unlock the bubble deployable asap, stock up on them while using your red cells on trap/guard stuff, they WILL make things easier

If you're moving in a straight line, you generally only need to worry about traps directly ahead or behind you. the worst thing you can do is be indecisive when a trap triggers, either push forward, or immediately flee at the first sign of trouble.

While Usually unnecessary, jumping while grappling then NOT MOVING YOUR CAMERA will maintain your speed. you reach max speed pretty fast while grappling so this can be used for long jumps that most builders fail to test for.

The nastiest combo, and fundamental to most killboxes. the trick is to destroy the Incenerators from safety, so enter as the pistons retract, throw a bubble, and use grenades or volt lance to clear your next safe zone.

Here's an example:

Some killboxes replace the Incinerators with other traps, but the same solution applies.

A room where at least one surface has been coated with a bunch of acid. Often mixed with other room types to make a killbox. Keep calm and remember, Harv must have a path, you can grapple on ceilings and walls, and traps can't see you through acid (though.

A bunch of guards in a single room, locked with your lock of choice to prevent running through.

If they stand on solid ground and close enough together, a good grenade can do wonders. if it falls behind them bounce the grenade off the ceiling.

The alternate crossbow is MADE for this room type if you can afford it, maxed out it has a clip of 15 which can kill 75% of the MAX GUARD CAP without recovering a single bolt.

Alternatively, if the floor is safe the trick is to KEEP MOVING. Enemies have poor aim, so if you're moving the only ones you need to worry about are ahead and behind. Try to stick to the outer wall as you go to minimize potential attack angles, but don't hug it if there are enemies next to it.

If they're armored aim for the weak points (above the head for bolt and bombs, below the legs for fliers, direct to head and back for big guys)

And of course when in doubt, flash barrier gives you all the time you need to pick them off slowly.

These tips will get you through the major killboxes. If you lack the resources or the patience, there's no shame in quitting to deny them kills and abandoning the base at base selection.

Remember, when building the most lethal option is whatever your foe doesn't expect and isn't prepared to deal with.

If there's a base type I didn't cover, post in the comments and I'll tell you how to beat it, or make it and send it to me and I'll beat it.