I wrote a PR that should fix the try_files behaviour.
https://github.com/caddyserver/caddy/pull/3684
If you have time, could you download one of the CI artifacts and give it a spin? fileserver: Fix try_files for directories, windows fix · caddyserver/caddy@db4828b · GitHub
I’m targeting v2.3 for this change because it’s probably too late to get this into v2.2 since we’re already in RCs for v2.2.