Bitwarden's docs say it's possible to bring your own certs[0]. The Bitwarden marketplace image on DigitalOcean asks whether you want it to manage its own certs or not. From minor googling, it seems you can change your mind later by modifying a yaml file[1]. HN threading isn't best format for support. If this still doesn't help, let's move the discussion elsewhere.

[0] https://bitwarden.com/help/article/install-on-premise/

[1] https://gist.github.com/kylerchin/00e6990706183ddb0e0e792a1c...