Have you seen http://sequeljoe.ohwg.net/ ?

I'm also following https://github.com/ragnar-lodbrok/meow-sql closely, a C++/Qt port of the FOSS-but-Windows-only https://www.heidisql.com/ .

But neither of these are really "fully baked" options.

EDIT: This may have come across as the typical HN "middlebrow dismissal" so I just want to say, phenomenal work and a heartfelt thanks for being fully FOSS. Tools like this are a really important part of the SWE landscape that could use some more good entrants.