Hello all, another Linux convert here.
I blew out Microsoft when they stopped updating XP, 10 years ago was it? Anyway, like Gary I had a number of programs designed for Windows, but what I found was that programs such as Outlook Express & Internet Explorer could be easily changed to Thunderbird & Firefox, I never actually used Microsoft Office as I didn't really have a need for all those bells and whistles, but Libre Office seems able to supply my limited needs & wants. One point in favour of these alternatives is that they have both Linux and Windows versions hence the changeover can be made much less painful by replacing the purely Windows programs with the Linux, more correctly Open Source, programs first, getting used to the new programs, then changing to Linux afterwards.
I also had programs such as Paint Shop Pro (PSP) & Design Cad (DC). These were somewhat more difficult, especially as Wine, an intermediary program, wasn't very good 10 years ago. PSP was eventually replaced by The Gimp, whilst DC isn't perfect, but with the increasing improvement to Wine, is now very usable. Incidently, I use an old version of DC as I really can't be bothered updating.
I also have a no longer supported DOS based database program called M-Pro or Masterfile Professional. I have got this working under Linux Mint Mate v.20 using an intermediary program called DOSEmu2. (There is an original version called DOSEmu, but that no longer works under Linux Mint.)
The only program I failed to get working was TaxCalc, but as I found the HMRC on-line program satisfactory, it wasn't that much of a loss.
So, my advice is to take it slowly, start with programs that have both Windows & Linux versions, then change to Linux (and the Linux versions) when you are used to the new programs.
For anything awkward, Wine these days is very good and does allow Windows programs to run reasonably well under Linux.
For DOS based programs, try DOSEMU2. There is another DOS Emulator known as DOSBox. My experience with that is that firstly it's aimed at the gaming community, and secondly, it requires a lot of effort to get it working.
Finally, FWIW, I have my machines setup to emulate the XP desktop as near as I can do it without delving deep into the Linux innards. I don't bother with pretty background pictures, using instead black background & white text. It all works for me, and I would certainly recommend changing over to Linux, not least of which because that way you can avoid the Microsoft "tax".
Cheers,
Peter G. Shaw