> And while they've recently announced more of this stuff will move to FOSS soon, at the same time their response rate to new bug reports has become worse than ever before, which is deeply worrying.

A huge chunk[1] of the MySQL developers were laid off (and also large amounts of QA etc.), so it's not surpising at all that they are struggling to keep the lights on. There are talks about an external group trying to form to take more ownership, but so far, your best bets are MariaDB or Postgres, depending on whether you think MySQL 5.1 was the epitome of relational databases or not.

[1] From what I gather, about 75%. In the first wave.