This seems to occur even on a brand new world, but only in 1.14.1. 1.14 is completely fine. The server just suddenly starts lagging like crazy, kicking everyone out and crashing because the ticks take too long. This can happen after anywhere between 5 minutes and 1-2 hours of the server running. But i haven't gotten it to run for more than about 2 hours max before crashing. With max-tick-time set to 1 it won't crash the server but instead kicks everyone out and after about 5-10 minutes people can join again. A few days ago i uploaded a debug log. If need be i can provide more.
I managed to fix my problems i mentioned a few comments above. I did so by installing every single windows update there was, defragmenting my hdd and reinstalling java. This might not help any of you at all but it might be worth a shot for those of you running on windows and not through some hosting site. I might just be lucky or maybe my issues were unrelated but thought i would share anyway. After doing these steps the server ran the whole day yesterday without crashing or freezing or kicking anyone out.