PrivateDNS Not Working as Expected and some other issues

[student8271]

So I followed AdGuard's tutorial on setting up AdGuard Home on a public server and set it up on Google Cloud Platform. I followed the instructions – bought a domain from Name.com and tried using the Lego thing to generate a certificate, as is mentioned in the AdGuard article, but I couldn't get it to work. I also tried using Certbot by following a YouTube tutorial but that didn't work either. I then tried using the certificate Name.com offers through Encryption Everywhere by following some tutorials, particularly this one from Namecheap and enabled encryption.

While generating the certificate for encryption, I tried getting a certificate for *.mywebsite.name (let's say that's what my domain is). The CSR was generated without issues. However, Name.com’s SSL generation page showed me an error, something about hostname mismatch. I tried again but with mywebsite.name instead (followed Namecheap tutorial for this) and this worked. Now when I go to the Encryption Settings page in AdGuard Home, I see "mywebsite.name" and "www.mywebsite.name" in hostnames. That brings me to my first question. How do I add a wildcard entry (with Encryption Everywhere if possible since it worked when I tried setting it up) so that I can use Private DNS as is mentioned in the tutorial by AdGuard (so that I can have private DNS addresses like "device1.mywebsite.name"?

Secondly, on the Setup Guide page, it says that I should be able to add "tls://mywebsite.name:853" to my Android smartphones. However, I can't add either. As soon as I use "/", the option to save gets greyed out. I have tried this on two different Android devices running Android 10 and 12. It works on the AdGuard app, though, on both devices.

Thirdly, on devices where I am using the AdGuard app as well as my iPhone and iPad where I have set up DoH using the configuration profiles, I am seeing multiple entries for every request – A, AAAA and HTTPS. Is there a way to hide the duplicates?

While I have managed to set things up, I am in no way an expert on GCP, generating certificates, etc. In fact, I consider myself as a beginner who got lucky so far with this project. I would request that you help me but please keep it as simple as possible.