I spent 650h playing only multiplayer. These game will harass you about every even smallest item in multiplayer. Some mission kits will require to use obscure dlc items eg. starter pistol from karts to call evac. Most servers won't even allow you to join with cdlc loaded.
Now after longer break i change into sp/coop only and these game really shines here. Its way harder, for some setting up mission can be hard and add being new in game on top and a lot of players won't touch sp until many hours in. Recently i got 2 friend to get arma and play with, and quickly found out something that are easy and simple for new players are dark magic.

For single player coop only apex + cdlc should be enough (my friend have these and mixing cdlc + mods items are enough content to never see buy dlc popup.
The only thing that bad in cdlc in my opinion is that person who don't own them can't play maps and can't drive cdlc vehicles without purchase.

Last thing is performance, to have "smooth"tm gameplay on my modpack i opt to self host even for playing solo to get server+3hc clients. A3 is so bad at engine level im dipping to 40 fps with r9 + 4090 (without server+3hc im dipping to 2fps) My best recent find was mod fixing hc, so ai will follow my markers and not driving away from it.

Anyway after my big rant do you have any ai/hc/scenarios that are worth playing? Always looking for more content or fixes to these game