FPS Issue on server

Good morning!!!  Hello,  I am an owner of a realm and my community and I have started to notice fps issues at my woodland  Mansion.  Note that we live in a pre generated house with 6 floors,  but only experience lag/fps problems one the first 3 floors of when you look at the house.   Honestly I have no clue what it could be,  I've done multiple test to diagnose where the issues are coming from but all results lead to the same places, no where.   I've checked taken out or beacons, our auto sorting system assuming that was the problem but nothing.   Still bad lag/fps issues here at this one place in the server. I'd really appreciate some help, thank you

Nick/prodigygamer2