I still can barely play fda in queensland australia, I have never managed to get 10 games to get ranked. And I don’t think I have ever played a btb which I would really like to! All the other modes generally work fine 
Free for all is one of the least populated playlists in the game. Take into account that your region generally has less players, the skill matching and other factors and it’ll usually result in “unable to match” errors.
They’ve tried making the region restrictions less strict, but that was met with issues from both the Australian players and non-Australian players. Aussie players were saying while they now find matches, they had extremely high ping and latency while non-Aussie players complained about games with higher latency.
The matchmaking team is continuing to make more adjustments every so often to make matchmaking smoother but at the end of the day, not much can be done about a low player amount in a playlist.
That’s fair enough but btb is social, should it really worry so much about lag. I just want to try it out haha. Though I must admit their system seems to work on cutting out lag, I’m on quite slow speeds and have never really noticed any, much better then some other games