Getting kicked from dedicated server after 10 min

[Belgianbuddy]

So I've been on a server with 2 collegues for a month now with over 160 hours of playtime.
But yesterday I started to get kicked out with the message connection to the host has been lost.

I've tried almost everything now.
One of my smart discord friend ran the server aswell to get some logs from what happend when I got kicked and he told me that as soon as I delete something the server thinks there is nothing or something that I'm not synced and that's why I get kicked.
The thing is after I loaded our saved world I could play but when my collegue joinen he then got kicked with the same message.
I'm afraid our world/ Saveworld or something is corrupted.

The owner sadly didn't take many saves of the world so I don't know what we should do.

Any tips what we could do without losing to much progress?