What do you mean specifically by super competitiveness that you get in games like COD? My experience of COD has always been that its a completely casual shooter in terms of the gameplay, but do you mean in terms of the toxicity/attitudes of players? In my experience that's at least as much an audience demographic thing as it is the game mode itself.
Will you be playing solo, or with friends? I found Warframe very fun as a super relaxed co-op shooter. Also Quake Champions might be a surprising choice but I found that because of the niche appeal of Quake and small community that its friendly and chill, especially the Clan Arena mode. And at low skill ratings i believe it autofills with bots and the AI is really not bad at all, can be a lot of fun for just casual bot games too I do this to warm up often or if I'm on a long phone call.
Valorant is launching soon and when it does it will be super casual because all the new players won't have a clue what to do while learning the game, so playing on the launch of the game and letting the matchmaker/ranked mode take you to the correct level will probably end up being really casual, and the gameplay is well suited for that I think.
