I finally exported all of my passwords from Firefox and Google, then deleted all of the passwords from both accounts. Also turned off their password saving options.
Dumped the exported data into my KeePass database (synced between all of devices via syncthing - works very well) and have been slowly going through it, sorting entries not already in KeePass into their respective folders within the database (I've used KeePass since high school, I have a system π ), deleting duplicates, and changing insecure passwords/adding 2FA as I come across them.
After everything was imported to KeePass and backed up, I filled the CSVs with random numbers and saved them, a few times, then permanently deleted them. No version history either.