If you REALLY want to, you can use this, but this is mainly for myself.

Currently it serves 2 apps. To add it to your F-Droid client, scan the QR code (click it to enlarge) or use this URL:

https://fdroid.repo.herkulessi.de/repo

If you would like to manually verify the fingerprint (SHA-256) of the repository signing key, here it is:
58 38 0A CC A7 AC 9A 98 10 75 27 AC 5E 35 97 0A DC FC 62 4E CA 4B 92 F8 4C B6 33 56 E3 A2 CC 39