Battlefield 6 hit a peak of 747,440 concurrent players on Steam on its first day of release. 

Battlefield 6 (abbreviated “BF6”) launched on October 10. On Steam, its first-day peak concurrent player count soared to 747,000, surpassing the 520,000 peak from its August public test. Tom's Hardware

That’s a big leap compared with its predecessors on PC:

• Battlefield 1 (2016) peaked at 53,000 concurrent players
• Battlefield 5 (2018) hit 116,000
• Battlefield 2042 (2021) reached 107,000 

It’s fair to say BF6’s popularity has already far outstripped all its predecessors.

Not only does it dominate within its own franchise, but the achievement is also impressive when compared to other games. According to SteamDB, among FPS titles, only PUBG, CS2, and Cyberpunk 2077 (each of which has once surpassed a million concurrent players) currently rank above BF6’s Steam numbers. steamplayerstats.com
BF6 has already overtaken the highest concurrent record previously held by the Call of Duty series (491,000). Tom's Hardware+2GamesRadar++2

Across all genres, BF6’s peak puts it in 14th place on Steam—just ahead of BanG Dream! (Goose Goose Duck) and just behind Baldur’s Gate 3. steamplayerstats.com

In terms of gameplay, Battlefield 6 offers both multiplayer and a single-player campaign. In multiplayer, players can choose from four classes to engage in combat. The single-player campaign has players assume the role of a U.S. Marine in various operations.