> Not adding the domain to Google Search Console immediately.
I don't understand. What is Google Search Console, and should I add all my domains there right now?
But if you do - you would get some notifications from Google about that website/domain.
I've only ever seen emails of the "There's an increase in 4xx/5xx errors on site/page(s)"
In Bitwarden they allow you to configure the matching algorithm, and switching from the default to "starts with" is what I do when I find that it is matching the wrong entries. So for this case just make sure that the URL for the service includes the port number and switch all items that are matching to "starts with". Though it does pop up a big scary "you probably didn't mean to do this" warning when you switch to "starts with"; would be nice to be able to turn that off.
You don't need to have any real/public DNS records on that domain, just own the domain so LetsEncrypt can verify and give you SSL certificate(s).
You setup local DNS rewrites in AdGuard - and point all the services/subdomains to your home servers IP, Caddy (or similar) on that server points it to the correct port/container.
With TailScale or similar - you can also configure that all TailScale clients use your AdGuard as DNS - so this can work even outside your home.
Thats how I have e.g.: https://portainer.myhome.tophttps://jellyfin.myhome.top ...etc...