Frankly, given what we've seen with LastPass this past year alone, there is absolutely no one I would trust to host any of my credentials.
My TOTP seeds go in a Keepass database that has a very long passphrase. That database is then sync'd across devices with syncthing and included in encrypted backups.
Out of all hosted options available that I lasted tested 2-3 years back, Authy is the only one that reliably syncs and backups seeds across devices. I would switch in an instant if something like Bitwarden comes up but for 2FA only.