I can’t host it on the official Fdroid repo because it has a separate build process than if it was an Android Studio app, and I don’t know if you can use the command line to build it easily.
Check out Repomaker. Its looking for a maintainer (has some outdated dependencies), but I’m pretty sure this tool still works as intended. It makes this very easy (point and click).
Also check out servergitmirrors in the example config.yml from fdroidserver, there it explains how to publish repos to github/gitlab. It is pretty straightforward
I know this is kind of the “simple” way to do this, but I have a local repo in a VM that I just sync to Github using git whenever I run fdroid update. The repo keys &c. never leave the VM and it’s only online long enough to update the repo.
Then I just set up Github Pages to serve content from the repo.