All of my paintings are being destroyed in my 3 year creative build

A while ago I got every different armour trim set onto armour stands in my 3 year creative build that I have poured at least 300 hours into but in 1.21.100 when I leave the world and reopen it any paintings in my field of view and one’s even behind walls break and they sometime lie on the floor and I tested it in a different world and when I summon a bunch of armour stands and left the world the (about 700 armour stands) created lag and ripped a bunch of paintings from the wall please fix this it is overwhelming me that the fact all of my hidden rooms on my (still single player world) are now just signs and holes in the wall please fix this.