Ex (fairly senior) GCHQ-er here (retired after 35 years). Since you mentioned the option of a degree apprenticeship at GCHQ I thought that I would chip in to note that although GCHQ certainly isn’t perfect as an employer one thing that they are very focused on is inclusivity and would be required to take into account any disability in the recruitment process (you would clearly have some sort of medical evidence) and also to provide appropriate support where needed (the Disabled Employee Network is very active). The degree apprentices also get to work on some really interesting stuff (at least the ones in my area did) - if of course you like that sort of thing (and I appreciate that some here wont). I’d also recommend the cyber degree apprenticeship rather than the software engineering one - the work is much more interesting.

I can’t offer any medical advice but I’d reiterate the suggestions to slow down a bit and take time to heal properly - in the big picture an extra year won’t make any real difference.