Request for noob networking help for a software engg (Tailscale, custom domain, dokku)

I'm a software engg - I've been following this sub for a while and finally decided to scratch that itch and set a homeserver up with a spare laptop.

I'm posting it here so you can tell me if I'm looking at an XY problem and if much better solutions already exist :D

Here's what I wanted to do: Run apps on the laptop, access them easily on my other devices (laptop, mobile) via a domain I own, shut them off to the external world.

I got Paperless-ng up and running via Dokku. I installed Tailscale so that it's accessible only on my other devices.

The problem now is the custom domain: is there a way I can set up a domain I own (say f.dvsj.in) to resolve to that laptop when connected to Tailscale? The laptop does not have a static IP, but Tailscale magic DNS seems to point to the latest IP consistently.

So is there a way to do f.dvsj.in -> dvsj-magic-dns.ts.net -> actual IP?

Or am I taking a completely wrong approach - should I ditch Tailscale and just set up DDNS with fail2ban and good firewall settings?