I'm being a bit flippant, I'm sorry.
It's just that what you're asking for is incredibly difficult. It is difficult enough to create a ELO-style rating for individuals in a pair-based game, and it is difficult to convince people they aren't as good as they think they are (since they've been in this "masterpoint increase" mode forever, as opposed to "ELO from day 1". There's a joke that "90% of bridge players are better than their partners", says poll). Everyone wants someone at the table slightly better than themselves ("as good as themselves") as a partner, against opponents that are slightly worse. Obviously, that can't happen either.
Yes, the perennial pickup pool is a problem, and I've offered suggestions
about this before. The problem is that a compatible partner is much more than just system and "level", even if you can define level sanely. It's style ("are you going to need your blood pressure pills when I drop QTxxxx for my weak 2, or will it be 'nice to see you actually have your bid for a change', or somewhere in the middle?" "are we reading defence the same way?" "Are there other ways to look for slam than Blackwood?"), temperament ("Are you going to snipe at me for every mistake you see at the table? If not, are we going to discuss things after the game? Or is it just 'only things I don't understand that we need to agree on' that is discussed, everything else is just 'play is fun, not work'?"), speed of play (or not),...
I agree that if you're looking specifically for SEF players, you want to look for French tables. That you can do. If you were looking for Precision partners, that would be a whole different world, or if it was important (say, in my case) that the table language was Spanish, then there are other issues (I may live in México part time, doesn't mean my Spanish is good enough
for bridge!)
There is also the "I'm this good, unless I'm just blowing off steam, then I'm this good, unless the kids are clambering all over, in which case I'm this good..." problem.
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)