Suteki Photography said
I've been happily using PS Elements 8 ,,, I can't install ....
until now I've done basic editing of raw/dng files
Which is similar in terms of user interface?
For basic editing any of the tools should do the jobs.
For some range of values of "basic".
Interface:
I once wrote a replacement program based on a database, which I made so far as was possible keystroke-identical with the no longe maintained old software.
You won't find that in this class of software.
My approach to such programs is to look at the functions, and regard all word-processors for instance as basically equivalent in most things, however much they conceal it (and however nasty under the hood.)
Similarly, although their are cosmetic differences between PS and the Gimp, they are obviously doing the same sorts of things in the same sorts of ways.
Going on from that, if you have learned processes, rather than how to work PS of a particular version, you shouldn't have vast trouble.
I use the Gimp and a little DarkTable. I've never used LightRoom but I gather there is some similarity.
Those are free - libre which is important and gratuit which is nice. Have a copy, have ten, give them to your friends. Support ... can be found, asked for, bought , or a group established.
Affinity has a good reputation, if you want to buy something with some paid support.
Alternatively:
Can you install Windows 10 in a virtual computer running under the Windows 11 operating system on your new one?
Can you simply install Windows 10 on your new computer? (MS licences used to include downgrades to previous versions.)
Are you annoyed enough to migrate off Microsoft to Linux (eg Debian or Ubuntu) and run FLOSS on that, and perhaps your licensed copy of W11 and W10 in virtual machines on that?
Can you pay someone to fix that up for you?