I accidentally ran the command '/bossbar' on my MC server. Since then it's always been laggy. Lately it even crashes a lot. It always throws the warning

[10:14:40] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running ...ms or ... ticks behind

until 

[10:18:48] [Server Watchdog/FATAL]: A single server tick took 60.00 seconds (should be max 0.05)
[10:18:48] [Server Watchdog/FATAL]: Considering it to be crashed, server will forcibly shutdown.

I will attach some crash reports. I tried looking into them myself, but I can't figure out anything from them.

I also downloaded the world and started it up on my local machine as a single player world. I did start a /debug session for some seconds and I will attach the report. My local machine is a lot faster than the server, so it might deal with whatever is going wrong better, but I still get those warnings on my local machine:

[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick.levels.world minecraft:overworld.tick.entities.regular' took aprox 177.425314 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick.levels.world minecraft:overworld.tick.entities' took aprox 179.857524 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick.levels.world minecraft:overworld.tick' took aprox 192.894467 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick.levels.world minecraft:overworld' took aprox 193.034123 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick.levels' took aprox 193.499615 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root.tick' took aprox 197.86466 ms
[17:59:45] [Server thread/WARN]: Something's taking too long! 'root' took aprox 198.083452 ms

We don't have anything crazy large like a gigantic monster farm, we only have four players at a time, we don't have any big buildings or anything or suuuper huge animal farms.

We do have some animals of course, but even when standing somewhere far away from those, it still lags.

The world did get quite huge by now, since we explored a lot already, but as I understand it, that shouldn't be a problem either since MC is only doing work for chunks near a player.

I hope you can help me fix the issue. It might not be related to the /bossbar command, but since the lag increased steadily.