Great idea! I think you need to define more clearly the "etc." bit.

- UK-France-Spain-Morocco - no problem, although bear in mind COvid19 concerns.
- Morocco-Algeria - I believe that this border remains closed.
- Algeria - better than it was, however you need to think through how to ensire security. Some areas are OK, others remain a concern. We were last in Algeria a few years ago, I know Algeria reasonably well, and so was not particularly concerned, however you may be better off heading south on the west coast, particularly when you consider...
Libya - I think it's fair to say "forget it"
- Egypt - you won;t be able to get to Egypt from Algeria (see above) - Egypt itself is more or less OK; once again, I'm familiar with the country, however haven;t been for a while. If you decide to travel via ferry from Europe (leaving out Morocco etc.) then note that paperwork is a bit inconvenient, but possible.
- Sudan - I'm not familiar with Sudan, however understand that there are no big issues.
- etc. - the "usual" route is from Sudan to Ethiopia (South Sudan is still insecure), then Kenya (some areas are insecure, however the main central and western routes are OK into Kenya. Then, to explore East Africa you'll presumably want to visit Tanzania, Uganda, and Rwanda. This area is no problem. We were last there in 2017 and had no problems.