To add more data to my analysis,by double checking the steam charts,it's the worst game of the current fighting game with Fighter Z in terms of number just behind MK11,at 3x less than melty/SF/DOA at 1K players.
Tekken is the best of the lot at 8K concurrent players on steam.
If you're playing on console (old gen),you can at least give a x1.5 to all those numbers,and add it if crossplay exist.
You're gonna run a lot into the same people at your rank,but other than that it should be playable.
Even the nickelodeon game is worse than tekken even tho it came out the 5th of this month,and it's way more casual friendly,but I guess there has not been a lot of content creator hype for now.
Fighting games have always been a niche genre,so the more games exists,the more fractured the community is,it's just how it is.
It kept its numbers quite decently before this huge 2-month drop,so I can see why the feeling is that it's "dead".