Just follow the instructions on PCGW: there's a custom installer and an unofficial patch. Install those and a graphic wrapper and you're good, the unofficial patch recommends cnc-ddraw, but dgVoodoo and DxWnd also works nicely if you prefer those (I much prefer dgVoodoo's scaling options and DxWnd is usually better if you want to run windowed).
appiah4 wrote on 2021-07-06, 13:57:OpenRA does not run the complete campaign as far as I know.
It also quite noticeably is not Dune 2000 at all. Might be a fun multiplayer game, but it doesn't play remotely like Dune 2000.
appiah4 wrote on 2021-07-06, 13:57:Gruntmods seems to be a good way of getting it working but I'm not sure about how accurate it is
That's basically a pirated version of Dune 2000 packaged with a custom campaign and unspecified patches. I would avoid it if you only want to play the original campaign.
appiah4 wrote on 2021-07-06, 13:57:PCem seems to be the only way to emulate a Slot-1 PC with enough grunt to run this but I'm not sure how demanding the game is - would this work on my Ryzen 2600?
I don't think PCem is well suited for gaming. It still has too bad input lag / frame pacing and its scaling options are not great. I would only use it as a last resort, or for testing things.
appiah4 wrote on 2021-07-06, 13:57:Custom installer and running it in Windows 95 compatibility mode under Windows 10, but I doubt this would be a good idea at all
It's not. Windows 95/98 compatibility modes under Windows 8+ introduces some nastiness that should generally be avoided (mainly performance problems, but they also conflict with graphic wrappers).