One thing that is not particularly popular in modern shooters are bots but that is not stopping EA DICE apparently since Battlefield 2042 will have mandatory AI soldiers.
AI enemies and allies in video games are usually not that capable which means devs have to compensate for their shortcomings in order to remove the risk of these units being obsolete. That is why you have the usual gimmicks such as bullet sponges, infinite reinforcements, wallhack and aimbot on AI characters in various games and that is also why it's problematic to put them into a multiplayer shooter - it is extremely hard to balance them out.
This appears to be a challenge EA DICE are willing to face as they opted to have mandatory AI soldiers in Battlefield 2042 . They talked about the topic in length on the official blog post but it basically boils down to backfilling the large teams since we will have 64v64 combat in the main modes and maps.
Furthermore, players shouldn't meet more bots than humans in any circumstance other than choosing co-op or having extremely few players around, like at the start of a match when teams are still getting populated.
Bots will also not occupy spots permanently and if a new player joins, a bot will be removed just like that. Overall, this should lead to having rounds that are more consistently 64v64 without preventing players to join a server.