I finally exported all of my passwords from Firefox, Google, and iCloud, and dumped it all into my KeePass database (synced between all of devices via Syncthing - works very well). I've 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 😅), deleting duplicates, and changing insecure passwords/adding 2FA as I come across them.

After everything was imported to KeePass and backed up, I deleted all passwords from both accounts and turned off their password saving options. Also changed the "password autofill" option on my Pixel to Keepass2Android, so it's now the only password handler on any device I own.

Also filled the downloaded CSVs with random numbers and saved them, a few times, then permanently deleted them. No version history either.