When entering  a 21x21 area on my minecraft server, me and friends will lag our games when we enter these chunks. Our games freeze when we enter, unless someone else is already within those chunks. 

There isn't a large amount of entities within the area and we assume it has to be an issue with the chunks loading. We have tried the /forceload command on the chunks but that didn't change anything.

We also have a few datapacks on the world, unsure if that will cause it but I thought it would be worth mentioning. 

Please check the attatched youtube link for a video as I was unable to upload it here due to its size.

Thank you!

https://youtu.be/drfXbZrwOGI