AirDrop/Quick-share FOSS alternative to transfer files across cross-platforms (LocalSend): https://localsend.org/
LocalSend is available for Windows, macOS, Linux, Android, and iOS.
It's free and open source, source code is here: https://github.com/localsend/localsend

I use KeepassXC on my laptop (completely offline), export the encrypted backup copy and store the backup offline copy and in cloud. Also, I manually import the backup file into my Keepass2AndroidOffline android app (it's a hassle, but I'm okay with it)
But for normies (non-technical folks), the benefits and convenience of using a cloud-based password manager is far outweighed by any security vulnerabilities in such password managers.
Also, Bitwarden's source code is open-source (unlike other closed-source password managers), so I trust it more.