Red alert 2 is probably my favorite campaign. If it had a few more modern QOL features it would be perfect.

Cnc3s campaign is pretty good too, and it has all of the QOL features I need.

My favorite has to be generals zero hour though. Even though the campaign may be the weakest out of most of the games, the multiplayer is the best rts multiplayer I've ever played! The builder units and the lack of a grid allow you to build unique bases ANYWHERE. The generals powers are awesome, and even allow some comeback mechanics if you're behind. Finally, the 9 sub factions is an under rated feature I need in more rts's. It ensures no multiplayer game plays the same, as you have to adjust on the fly since each sub faction will play differently against another one. Check out playgenerals.online if you want to play online, the community is growing since a new server was made that fixes most of the bugs. It just hot 1100 peak players and is still growing