If you have manually installed dozens of mods and the game is a mess of "Red Errors," the most stable fix is often to switch to a BetterRepack (currently RX series).

: High-resolution character cards (1MB+) with heavy overlays or excessive accessory slots significantly drain resources. Reducing the complexity of character cards can stabilize performance . 2. Essential Plugins and Technical Fixes

Akihiro moved the slider one notch to the right.

Before trying manual fixes, the absolute best way to fix 90% of crashes is installing the latest HF Patch for Koikatsu/Koikatsu Party.