RTS campaigns are never good and they never really have been. Most of the time it's either a boring slog with the enemy given some sort of random artificial advantage or it's an annoying mission that has you controlling a handful of units in a way that generally breaks most of the features that make you want to play an RTS game in the first place.
I truly don't understand the people for whom the campaign is genuinely enjoyable.
CoH3's campaign is just rehashed skirmish with some unique missions. Honostly, I only have 4 hours of gameplay in Coh3 because the campaign was boring.
Most RTS I would say have a good campaign that at least has more thoughtful mission design than just skirmish.
Age of Empires Series to include AoE 4
Command and Conquer Series. Even CnC4 had a more thoughtful campaign than CoH3
Supreme Commander
Starcraft and Warcraft
The skirmish mode could be better if they actually improve their AI. If Age of Empire's 2 AI could heard deer, then CoH3 AI can atleast find cover reasonably.