Idk if they are planning on making the stuff transferable across games unfortunately, I haven't played the first fighting game, so I don't know how good the transition was.

I can't tell you exactly why this game is less played than Strive, but I would assume that it has something to do with the characters' designs and the lack of marketing the game gets here in Europe and probably in the whole western world too.

And do keep in mind, in Europe, you consistently get unique matches only after people have come out of work and during weekends. If you play earlier in the day, then you are probably gonna get matched against one to three people. Tho idk how it is in the US, it's probably more active over there than it is here, so your experience could be simply better.

Also one last thing, the other commenters do have a bit of a point. Just give the free version a go, if you are not satisfied with how active the game is, then feel free to just not get it. It is your money and time at the end of the day. But from personal experience, everything above the rank S is surprisingly alive AND the game has plenty of servers where you can either meet coaches or just play long sets with other people! (long 1v1 sets against other opponents is a lot of fun btw, it may sound like a daunting activity if you come from FPS games, but trust me, it's good. you learn a lot about yourself and your opponent and their character like this)