Hi OP. I'm also a twin mum, and I remember how challenging these days were. First, be reassured that you're doing a great job.
On the sleep front, I'd remind you that sleep issues even at this age are really normal. They just feel so much worse when you've got two of them and they're not necessarily in sync etc. For us, we found that having them sleeping in the same room created more disturbance. They were both noise, wriggly sleepers so they woke each other, and us, even when they weren't sleeping. At this age we had them in separate rooms and my husband and I slept separately too, with a monitor each. That way we only got disturbed by one baby at a time and we all got more sleep! Obviously I don't know your sleep arrangements, but I'd definitely try out different options and see what works for you.
On the feeding front, it sounds stressful for you, but you can be reassured that they're growing. The amount of milk is still reasonable and they are eating some solids. I think we sometimes overestimate how much food small babies actually need. Remind yourself of the guidelines and it might reassure you a bit? Keep offering different thing and do what you can -to get them to eat. I'd let them have more of meals/foods they like rather than stressing too much about what they are eating for now. I also would say that I don't think I ate myself enough around my twins - feeding two babies at the same time is hard enough work without trying to feed yourself at the same time! But if they aren't watching you eat much then maybe that might encourage them? Also, feed them when they are most hungry - food first, milk after - and don't worry too much about traditional meal times. Routine is helpful for your sanity with twins, but I don't think you need to stick rigidly to breakfast lunch and dinner times per say. Find your own rhythm for now.
We had feeding issues, albeit at an earlier stage than this, and tried so many different formulas and things, but it all resolved with time.
Also, in case you are worrying, staying at home is fine. I barely got out with mine at all when they were this age and smaller. Partly due to COVID, but also because some days it just wasn't worth the effort. We didn't do any baby classes or regular socialising. They started at a small local staffed playgroup when they were 2 and a half, three mornings a week without me, and they were absolutely fine. Now they are 7, school has been a breeze and they are flying.
So many things seemed impossible when they were that tiny and I was exhausted and overwhelmed all the time. But they do get there, gradually, and now I can look back and see that a lot of my anxiety was just sleep deprivation and needing a break. You honestly sound like you're doing really well.