Hi radman -
You’re on the right track with ideas for improvement, but in the meantime, I think you can accomplish a safe and usable backup of your BW vault by using a different browser to export a .json file (unencrypted) to a place that only you specify (Chrome, for example, doesn’t create any hidden temp files). Then use KeePass2 to import that .json file into a KeePass vault that you’ve given your own (separate) master key to secure. The KeePass vault is a single file which is easily copied to whatever backup medium you desire. And, you get the bonus of being able to open it and use it if needed, or just retrieve one lost/old password without having to clobber your production BitWarden vault by restoring an entire exported BW vault.
KeePass2 for Windows natively imports BitWarden .json files, and BitWarden natively imports .xml files exported from KeePass, so moving data-sets back and forth is pretty easy.