There was an interview pre-launch where they confirmed that SBMM is in the game "but a low priority factor, and depends on the game mode (higher in smaller TDM-style modes)".
Obviously the issue with that (and matchmaking compared to a server browser in general) is the complete lack of transparency, they can tune it at any time without us knowing.
SBMM is clearly the biggest reason why they went from a server browser to matchmaking, server costs are just an excuse to distract from the obvious. They acknowledged in the BFV era that they changed the TTK to stop high fluctuation from newer and low-skilled players, next game (2042) they had matchmaking, make your own conclusions.
