Hey! I am....super new to birds - but not super new to special needs momming (as a mom myself, and as a behavior specialist professionally.) So take this with a grain of salt. Get a budgie. Keep it in a "safe space" such as your bedroom, where you can interact and bond with it but there are boundaries for your kids. I get it. I get it. Honestly. The burn out, and the homeschooling and the noise, and the mess (and partners who can't put their wet towels in the freaking laundry basket..ok maybe thats just me). You need something to love, that loves you back without the urgency of...neurodivergent parenting. You can do hard things, your kids can do hard things. My budgie is in my BUSIEST room (2 neurodivergent kids, and a neurodivergent me) and the first couple of days I was like....what have I done, the level of chaos in this house is...SO MUCH for a tiny creature but, the bird is truly unbothered by the chaos. I think because he is a baby maybe? He has no...calm to compare it to? Get the budgie. Love it. Learn everything you can. Your kids needs and noise won't be what they are now forever. ALSO (as a professional) outsource where you can for your sanity. Schooling, care for the caregiver groups. Treat your new bird with the same respect and relationship building you want for your kids - and remember it won't always be this way
I personally think you should at least get a pair of budgies. Budgies are SO social, and it's really important that they have a friend to interact with 24/7. Saying they're less tame in a pair is a myth, I have 4 budgies, all super tame, fully flighted, let me touch them, and they weren't hand-raised. So do a lot of people. It took me about 8 months to tame Stormy, and 1-3 months to tame the others. They love, love, LOVE my attention, and any attention, but it's still important that they have interaction when I'm not there with them. And I can give some perspective from the kids, as a neurodivergent (professionally diagnosed) kid myself.
Birds are stressful. I have sensory issues, and the screaming and squacking can be SO hard to deal with sometimes! And sometimes, I have meltdown. The birds DO NOT help! They pretty much think it's a funny game and start singing. The birds have taught me empathy, and I'm extremely grateful for that, however sensory issues and birds do not mix. ADHD and birds is also hard. I forget stuff, procrastinate, and they don't exactly help me do work or focus! Just some thoughts if you want to allow a neurodivergent kid in with such highly sensitive animals. And one of my budgies has a physical disability (he is unable to gain muscle in his feet, causing him to slip and fall constantly... the vet doesn't know why, but it's tough on him, not being able to grip) and a mental developmental disability (spatial awareness issues), so that makes it harder. I didn't intend to get him, I didn't even notice his disabilities until he had been home for a couple weeks. So you really never know what you get. You could end up with more stress, instead of less.
Good luck, though! I have a Red Eared Slider (don't get them unless you want a huge, 100+ gallon tank), and I love her. Maybe a small tortoise or a leopard gecko would be good?