I played Wildlands coop my first playthrough. It was a lot of fun, but it wasn't until I played it solo (with AI teammates turned off) on the hardest difficulty that it started to feel like I really needed to be tactical, which made the game a lot more fun. I eventually beat it like that and now I'm playing it again with all the hud (except the parts you need to know what you have equipped) and spotting turned off. I was about half-way through that when the first person mod came out so now I'm playing in first person as well. It can be very challenging, but that's what makes it rewarding. The AI is a lot better in this game than you can realize when spotting and third person are enabled. I always felt like the AI was way too blind and bad at finding the player before I played in first person because it's hard to gauge when they should be seeing you in third person but in first person it all lines up correctly and feels hard, but fair.
Just an example of how much more tactical it feels, in my first playthrough I don't think I ever used flash bangs. In my current playthrough they are incredibly useful. Same with flares. Thermal is WAY more useful. In my first play through this game felt like Far Cry(easy action, run and gun), now it feels like an open world Splinter Cell game.
The first person mod isn't perfect, like the camera height in cars is often too low which will make you want to drive cars with big windshields but other than that it works really well.
If you have any desire to play the game again, I suggest playing on max difficulty with the AI teammates turned off, in first person, with as much of the hud disabled as you can get away with. Just know it will be challenging. Play slow and stealthy.