I realize that Combined Arms is a Co-Op mode, but it says you can play solo. I applaud your effort of trying and adding something new to the game. At first glance it appears to have a Ghost Recon Wildlands or FarCry feel to it, but once you get into it playing Solo, they are different because there is not as much stealth. I find myself guns blazing, even on easy mode, every match.
In GRWL and FC, you could usually spot enemies from afar. These enemies would walk certain patterns, you could get used to the route they walk and use stealth to try and take them out from behind, leaving other enemies unaware. In CA, enemies seem to be grouped up more with less walking making it difficult to use stealth. I can't last long without getting spotted in some way, forcing the guns blazing method.
So here are some suggestions to help with the gameplay, unless the sole reason behind it is to just go guns blazing.
-Higher elevations to try and spot more enemies on some maps.
-More walking routes by enemies.
-More silencers available.
-Ability to build more ammo crates to resupply explosive rounds when facing multiple tanks/armored vehicles.