I've got my first 2 suppressors still sitting in jail, so I'm no expert, but here's what I've learned from my own reading and being around other people's suppressors
You could get one 30 cal can to fit your needs and use something like the Silencerco ASR mount to switch between. It'll require a compatible muzzle device for each rifle but switching is pretty quick and easy
On bolt guns you'll be hearing safe, on semi autos (like ARs) you won't fully be hearing safe because of the ejection noise. All good suppressor companies list the dB rating
Suppressors also function as good or better than muzzle brakes for recoil reduction, and I've heard they can increase accuracy and velocity on some rifles.
The buying process seems daunting but it is super easy.
Hope that helps and I'm sure someone with more experience will chime in with more info