Could you run an ACME Client (like Certbot) on your BitWarden or local system using the DNS Challenge?
If your DNS provider has an update API that is supported with your chosen ACME Client you can even automate that. Otherwise you could use a manual DNS Challenge so you'd have to act to get a fresh cert every 60 days or so. But, your current process is very manual so this isn't much different.
Had you provided more answers to the form you were shown we could give more specific advice. And, sorry that no one picked up earlier.
That all said, wasn't much of this covered in your previous thread? What is different now that a DNS Challenge would not work?