I've been watching from the sidelines and it is still really tough exam-wise. It depends on having a good centre which is willing to work with you and also having someone who can provide assessed grades, who will be acceptable to the centre. Many kids have missed out.
There are a very few exam centres run by home ed families (FareGos for example) which have been really helpful, I understand. Of course they are swamped by the increased demand. In my area there's an exam centre which has always been renowned for its willingness to arrange whatever people need... at a very high price. Those who could afford it have got their CAGs there.
Many people have worried that the already scarce availability of exam centres will dry up further. Some centres have been very helpful, but of course its a huge time and effort for them, which their modest fees haven't covered. They have no obligation to take private candidates and after the last two years they may well decide that it's too much trouble to continue doing so.
I think you're right to be concerned. On the other hand, if your daughter's anxiety at school is very bad, it may be that home ed is the best way forward for her despite the potential exam problems. It would be wise to have some backup plans in mind. How set is she on doing the exams in 2022? I know a few people who decided to delay for a year in hopes that better solutions will be available by then. It's possible to sit some GCSEs at college, either as part of 14-16 provision or after the age of 16. It won't be the full range of subjects normally available at school or through HE, and might not suit a very academic child, but it's something.
Local home educators will be able to tell you more. If you join a local Facebook group, you can ask where and how people are doing exams. Nobody has a crystal ball, but they may have some idea whether particular local centres or tutor arrangements will be useful to you, or will tell you where they are travelling to. I'd be cautious of signing up to a long contract with any online school if you don't know how and whether your daughter can actually do the exams or get CAGs. Some online schools simply provide the education and leave arranging the exams to you.