What happens to me during migration from ESA to UC?

I'm in an odd position, to be honest, and not one I'm comfortable with. It's not as simple as migration, it's making absolutely sure that I don't mess this up. Having just been forced to move house has been a real wake up call for me. I'm struggling with every single little aspect of our lives and have had to accept my capability to deal with everyday stuff is way less than I believed. It's a shock. I claimed PIP before the pandemic, while on a waiting list for diagnosis for Autism, and was awarded high care, low mobility. It was a lifeline as I couldn't get my hands on enough evidence for my husband to successfully claim PIP despite diagnoses (having been on DLA since he was "honourably discharged" from work). I'm one of those people living on the fringes, hoping that somehow life will get better but it hasn't. I'm sure many out there are in the same boat. Eventually at Tribunal (paper hearing) they accepted my husband's numerous conditions and awarded him the top rate. 12 points straight off for both, so they didn't fully score him, they said. After diagnosis (ADHD/Autism/Complex Trauma) I was told to see a Neurologist for other issues identified by the diagnosing psychologist but the waiting list was closed to all but really physically impaired folk. Meantime my PIP was extended because of Covid. My review came up. It took them over 18 months to deal with it. Long story short it went to Tribunal but the hearing was on the day I moved house (I had no idea). I got an email from them saying they felt they didn't have enough information to make a decision and a letter was to follow. This is pivotal; and I can't get my hands on the letter. It's been 3 weeks since the hearing, and I don't know what to do. My address was changed the same day, but they'd got the flat number wrong. I need the letter, have sent numerous emails but have no clue what's going on! They say they have corrected the address I can't get into the MyHMCTS account as it sends me round in circles with verification codes…I thought perhaps any letter would be on there? I got into some part of gov.uk which is how I know they messed up the address but can't find the Tribunal info on wherever I was on there, I can't concentrate for long enough to figure out how I even did that. I think the hold up is that I "care" for my husband, according to my GP surgery and I understand this makes decision making more complex, but I've been totally honest about our whole situation. I don't consider myself anyone's carer as I can't properly look after myself and don't consider myself the right person to be running this circus but don't know how to get help, so we're bumping along the bottom all the time, with me scared out of my mind 24/7. Having splurged all that, husband claims a combination of contributory and income based ESA in the Support group. The HB claim is in my name. Husband has PIP at full rate (which will be due for review any minute). That's it. So I don't know what I'm supposed to do for the best. I don't claim carer's allowance. I don't really know anything about it. We can't carry on like this, we need a grown up!! I'm being light-hearted when I say that but I mean it……how do I navigate all this????? I'm sorry for waffling on people. Hopefully you can understand what I'm on about. This took me since your replies to cobble together, to give you some idea of the struggle!!