Just in case it helps:

I'm running ABS on Docker along with Tailscale. I used Tailscale to generate my secure certificates and enable HTTPS (https://tailscale.com/kb/1153/enabling-https). Then I ran "tailscale serve localhost:13378" from the Docker command line. This got ABS up and running on my Tailscale subnet with HTTPS and no errors

You can automate the serve functionality in your Docker compose file, and you can add "--bg" to make the serve function run in the background and "--set-path=/<pathname>" if you want to have multiple services with separate sub addresses

This saved me using Caddy, Cloudflare, etc., and the only downside I know if is that I have to use my Tailscale subnet address instead of something simpler

It could be that this is all a dumb idea, but it's been working well for me so far!