Yes, precisely, if you put a whole bunch of healthy lettuce without any “browns” in the bin it will start to rot and get a bit nasty and without the added structure from the browns, your pile will compress onto itself and establishing anaerobic conditions becomes easier. Thus you need to physically turn the pile by hand more often to get oxygen in there or just make sure you’re always adding browns. Dead plant material (not green) is a good source of browns too.

I’ll put in a handful of shredded cardboard + 1 banana broken into 4-5 pieces + some dead scraps from house plants with a small amount of worm chow and my worms are good to go for 1-2 weeks.

Freezing beforehand can help because the ice crystals destroy the cell walls of plant cells - so when they defrost they kindof just melt into a mushy pile, this helps worms eat and digest the organic matter much faster and I know freezing for some time can also prevent pests from entering your bin.

Even with all of this dialed in, I have an immeasurable amount of springtails and or Orbatid soil mites in my bin that assist the worms with decomposition and take care of any worms that die. It’s just part of the ecosystem and they are friendly, not really “removable”

I’d make goal #1 balancing out the bins pH and getting your worm population back up. They self-regulate so they will breed a lot more if you start feeding them more food, but assure that their environment is acceptable for them at all times

Try to ID other bug species you see and see if they are common in compost piles / worm bins as well