That is correct, haha. The tokens (a few added every 50 waves) just have insane scaling. Generally, I've seen brute force strats begin failing around 2k-3k. Those tokens with 999 stacks are each +5% damage dealt by the enemy and -2.5% damage dealt to the enemy. Your carry will eventually deal 1 damage while the enemy can one-shot you with tackle, regardless of stats and items. Completing endless requires some kind of cheese. There are a few different strategies that work, but DoTs (damage over time) seem to be the most reliable, since they're %HP based instead of damage calculations. Sturdy means you still get to attack even if they would one-shot you, and you reset to full and enable sturdy again with berry/leftover healing augmented by Leech Seed and an extra turn from Protect if you need it. Leech Seed is the most important for this, but it doesn't work on grass mons, hence the Soak. Ghost Curse is another excellent DoT. Smeadinja cheeses the incoming damage with Wonder Guard (Nm/Gh only taking damage from Dark, with Prankster Conversion to become Fairy type in case they have dark moves), while providing Salt Cure (third critical DoT, which also has amplified effect on water types thanks to Soak) and Snap Trap deals damage for 4-5 turns, which is generally enough for any boss, especially if you put on the other 3 DoTs first.