I think it's ok to store your seed in a password manager, as long as you use something like AES to encrypt it first.
So even if someone somehow breaks your password and your 2fa (maybe left your device on), they still can't see the seed.
Discussion
One could also just store the segwit passphrase in the password manager, and not the seed.
Your seed should NEVER be stored digitally, and should be considered conpromised if it has.
That only works if every PC that accesses that PW manager is clean on every access. Keyloggers and screenscrapers will steal your coins this way.
You could store the image seed but not the pattern for a border wallet this way and be safe.
Interesting, I was not familiar with border wallets. Found an overview here:
https://bitcoinmagazine.com/technical/border-wallets-help-users-memorize-bitcoin-seed-phrases
+1
Generate seed phrase offline e.g. with sparrow or electrum wallet (on an OS setup from scratch), AES256 encrypt and base64 encode the binary. Transfer text to an usb stick and upload to a secure vault.
Or why not use steghide to embed the encrypted seed inside a picture and upload the picture to a cloud storage? Steghide allows you to protect the payload also with a password.
I do this for my hot wallets, but not for my hardware wallet.