I am thoroughly confused here. I suspect it’s multiple issues.
I have four different mirrors of the official f-droid repo in my repo list. From what i can tell, my phone connects to them just fine and claims it’s updated.
However, for example the Telegram Version it claims to be the current one is 5.5.0, while the f-droid website tells me it’s 5.11.0.
On top of that i have tons of apps listed as installed that i don’t remember ever installing, have no compatible signature and can’t seem to uninstall.
Not sure of those two problems are related, but it would definitely be nice to be able to get current versions again 
I am actually an IT professional btw. But i can’t figure this out without help 