The algorithm is not working as intended. And if it was this would be bad instead of terrible, but as is it is terrible. Let me tell you why based on my experience and analysis of how the algorithm works (I don't have inside knowledge of the code) ...
The system works by creating tables with a specific setup based on your preferences...but only 1 table even if you have a bunch of preferences that you are okay playing with (initially this would be something selected from the "I'm okay playing with" section). After some time the system will sometimes create a second table (4 hours I believe for turn-based), which theoretically opens up the level preference after the appropriate amount of time (plus the created table is selected from your "I prefer not to play with" section instead of another choice from your "I'm okay playing with" preference (for example my 2nd table opened up is 2 moves per day & +/- 1 level (both "I prefer not to play with" while the first is 1 move per day & my level (both "I'm okay playing with"). So it is using all "prefer not to play with" settings instead of just one, or opening up a bunch of tables with all the settings you are okay playing. So this drastically limits your ability to play to a much smaller window than what you are actually willing to play.
Now it is still possible to join others tables that you qualify for, and it checks this every so often. The biggest problem here is that this won't happen with level preferences with people of different levels because the level preferences would never perfectly match. For example when a silver player reaches the 4 hour time and a game is open with their "prefer not to play with" setting a game is opened up that is available for bronze and gold players; however, the bronze and gold players can't actually join when their preference opens up to +/- 1 level. In the gold example, the gold player is only opening to tables that are +/- 1 relative to gold (silver-platinum), so the silver +/- 1 table isn't allowed because it accepts bronze (even if no bronze players are there and it is the last slot to fill). So, due to this fact even if you wait long enough to open to +/- 1 level, you can't actually join tables with players at +/- 1 from your level because the table requirement does not match the personal requirement. So the only players matching the table requirement would be those at exactly your level even when the requirement is +/- 1 from your level. In theory once you reach the 3rd level of waiting you could overlap with someone in the 2nd level of waiting (a +/-1 game hosted by a silver player when you are at a +/- 2 level), however this also requires your other settings to line up with their "prefer not to play" settings, which is much harder to do than the baseline 1 move per day that almost everyone plays with.
Now, even if the system worked as intended and you could play other levels after the initial 4 hour wait to get to secondary preferences (or 3ish minutes in real time?), another problem arises, where in a popular game, all players at a popular level will always play people on their level (as they don't wait long enough to play someone from another level)...that sounds fine on it's own, but it can also mean people on the same game but an unpopular level can never find a game...they've waited long enough to be eligible to play someone from another level, but those opponents never have to wait long enough to accept someone from their level...hence you are forced to wait for all players from exactly your level...which never happens in (my brief testing) with silver league in 7 wonders.
