Reuse Bitwarden self signed certificate & pihole domain (http://pi.hole)

In my dietpi machine I have these software installed Home assistant, pihole, plex, proftpd, dropbearSSH & bitwarden. While we are installing bitwarden system made self-signed certificate to secure the connection. Is there any way we can reuse same certificate & secure other installed web based applications also ( “Home assistant, pihole, plex”) . I know within LAN HTTP or HTTPS not making any difference. But I already have all ingredient then why not cook the procedure to use them. I know this is area where reverse proxy, cady, swag or negix are expert. But I will thankful to anybody if somebody make easy guideline/steps for dietpi installation. I do not want Let Encrypt certificate I just want reuse self-signed certificate.

also i have domain url of my machine due to pihole (http://pi.hole). so my main target is discard all web request to machine. only allowed entry point to machine
https://pi.hole > Pihole
https://pi.hole:32400 > plex
https://pi.hole:8001 > bitwarden
https://pi.hole:8123 > home assistant

all http request convert to https requests and all local ipaddress of machine discarded (192.168.1.XX) only way allowed https://pi.hole


best to my knowledge, Bitwarden certificate is issued for the host name of your SBC. Means you would need to create a new self signed certificate yourself issued for pi.pole. Once done, you can configure web server you are using for PiHole to handle SSL and do revers proxy