• If possible, every U rank card
  
• If you haven't completed it, try getting 2 "tank" (just high influence would do enough, also you'll need lot of focus) and 2 supports (you would want only high focus on these ones cuz you are going to grind mostly talent)
  
• Patience with the Ultimate Talent Development Plan. If you need a guide, you can check out this one:
  https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1162344915
  
• Not a must, but it would be easier if you have high tier shoes (Speed) for your tanks. If you need more focus, you can also grind a bit for equipment, but with 600-800 should be more than enough

Since you are going to switch between tanks to use Sacrifice, the best talents (imo) to go with are the following:

• Sacrifice L10
  
• Wind Barrier (Doesn't have any L10 boost but it's best if you have it maxed)
  
• Fighting Spirit L10 (In case any of the support faints)
  
• Ultra Defense L10 (To avoid getting confuse. You can, however, get despair effect)
  
• Absorb Focus (Only take if you want to, useful when you have low base focus)

Yes, it doesn't matter any stat besides influence, focus and speed. Monokuma v3 will mostly (if not always) crit on his no-skill attacks. For his Wind Jet All, you don't have to worry as long as you have Wind Barrier on (You only take 1 HP with the barrier on). If, for any reason, you don't want to get Fighting Spirit, you can go for Energize, best if it's L10. I'll explain on the next part why would you want that skill~

Don't worry about level here. If you go fully talent board, chances are higher for getting every talent you'll need (but please try to beat every exam :)))). Talents you are going to aim for:

• Energize L10
  
• Poison L10 (Important skill btw)
  
• Fighting Spirit L10 (To revive any tank)
  
• Ultra Defense L10 (To avoid getting confuse)
  
• Wind Barrier L10 (In case one of the tanks faints and the barrier goes down)

As the tanks, you won't need that much of an stat development. Focus on talents instead to secure an easy win!

First of, a quick analysis of Monokuma v3. I'll take the stats from another guide, so if you want to check it out, click down:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1157409109
HP: 66666
Skills: Despair (will always do on 1st and 7th turn), Confuse (4th and 10th turn always), Wind Jet All, Summer Rain Fist
Resistance: Status

Thing to note: resistance doesn't means he won't be able to get an status effect. For this specific team composition, only poison is going to do the damage~

For the best playthrough, you would want to do this setup:

Turn 1

• Tank 1 uses Wind Barrier
  
• Support 1 uses Energize
  
• Tank 2 and Support 2 whatever
  
• Monokuma v3 is going to use Despair

Turn 2

• Tank 1 uses Sacrifice
  
• Tank 2 can do whatever
  
• Support 1 uses Awaken Poison
  
• Support 2 uses Awaken Poison

Awaken Poison can poison, but the trick is that is a chance (resistance is lowering the chance, not making it inmune). So for this, you would want to have both supports to use the same talent in order to almost secure the damage.

Turn 3

• Tank 1 uses Absorb Focus (if you want lol)
  
• Tank 2 uses Sacrifice
  
• Support 1 uses Awaken Poison only if someone died | Fighting Spirit if someone died
  
• Support 2 uses Awaken Poison only if someone died

Turn 4

• Everyone uses Ultra Defense
  
• Monokuma v3 is going to use Confuse

Really important to count the turns. If you get confused, take it as an instalost. From turn 4, you are just going to keep using Sacrifice, Awaken Poison if it goes away, Wind Barrier when it goes down, etc. Keep in mind, tho, that Monokuma v3 uses Confuse again on turn 10th. If you manage to do it perfectly, I'm pretty sure you can win before that turn (poison status takes 9999 HP/turn to Monokuma v3, so you'll need 7 poisoned turns).

If you managed to beat the boss, congrats! This is, imo, the easiest way to do it (in terms of training), since you don't need that much RNG luck for the UTDP. If there's any mistake, regarding grammar or typo, you can comment it here and I'll fix it (sorry if my english isn't perfect, btw). Now you can go enjoy your sweet achievement~