If you want to run your own Fdroid repository, it's quite simple to automate for releases from GitHub/gitlab apis. There's probably some way to automate it completely with GitHub actions even (I've been too lazy to learn to do it properly, so everything I do is just through local scripting on my computer, with netlify signing Fdroid releases for me).

Due to Fdroid being so slow at updating indexes on my older devices, I actually use a secondary Fdroid client (nethunter client also has a privileged extension) for manual updates, which only has my personal repos enabled.