You could essentially just stick with using a free Dropbox account, use your favorite Password Manager, ex. KeepPass, and save your password protected encrypted database backup to your Dropbox account, & load the file from another device, etc, Right?
I'm just too used to using password managers on VM's that i've never found use-case in syncing them between other machines cause that already sounds rediculously dangerous enough, next to storing them on your Untrusted web-browser. It sounds extra, but i'm that paranoid after personally experiencing getting 'hacked'.
Bitwarden is your best shot, it's the only open-source one that allows remote syncing across all devices. You can build everything yourself as well: https://github.com/bitwarden
Study the password manager solutions well (I am sure there are some posts for it)
Switch your frequently used first to get used to the new one and switch the rest at your own pace
It’s what freenas uses to back up to backblaze or any s3 bucket. Ive then verified the backups using rclone on ubuntu
I’ve used AESCrypt for a while. Open source and no major bugs found under a third-party audit.
However I find Chrome's password manager to be the best, especially when using different profiles for work/personal/etc
at the bottom of the site: "zero-knowledge encryption means that only you can access your passwords."
the data is locally encrypted, so the company in question never sees your data in cleartext. Generally with services like these your vault is unlocked with a master password.