Ahhh. Yes, I struggle with this since I cut out dairy and gluten (and now I get quite sick to it when I have it). However, I don't have the added sensitivities that you have mentioned. Soy definitely affects my endo - when I have an excessive amount (like two months ago), my pain is horrendous! I think it varies by person, but every now and then I don't think it hurts (in moderation of course). If you can though try to have it sparingly. It may be worth testing how you feel with more soy, but you'll take the risk of possible flare-ups with it.

I think it does have an effect, the question is the size of the effect. Technically, if you stand on a folded newspaper, you're closer to the moon. Functionally? Definitely still on the earth.

Sometimes sardines really hit the spot. Tuna on top of a salad was safe for me at my worst. If you can find it on sale, frozen flounder was kind to me. Chicken seemed safest gently poached in good broth, or roasted bone-in. I could sometimes do homemade breakfast sausage with ground turkey or chicken, but without a little pork in there it can be pretty dry, so coconut oil in the mix helps. Or I remember finding a recipe for chicken zucchini poppers, only it was loaded with garlic and that was right around when I discovered garlic was the death of me. Bean sprouts in a good bowl of pho.

This is the brand I use:
https://weliveconscious.com/product/collagenpep...
It's basically instant broth, but it does get you a little protein.

My understanding is that while soy can have some estrogen impact, it's very, very minimal. I don't think it should be a problem.

Are you a vegetarian? Or just your body having trouble digesting meats right now?

I've never heard of collagen peptides, will look into that. I can drink bouillon, so bone broth should be fine?

Eggs are definitely confusing. Some weeks I'm fine eating an egg a day, I mostly scramble them through my vegetables. But some days eggs are the sole cause of inflammation 😅.