Only one of my creative worlds is lagging so hard that it only responds 30 or more seconds later

Hello,

A year or two is when this started. I like to build a lot of different places from films that I enjoy, one of those being the castle from Beauty and the Beast. And after finishing the exterior and a few of the interiors everything was working fine. I found a tutorial on youtube that I used to a command block to make a few glass blocks smaller and fit a redstone torch inside it to act as the enchanted rose in the glass case from the movie. It turned out pretty well and I had no problems. Then later out of nowhere it started lagging so hard that the screen looks frozen. And every 20 - 30 seconds the camera responds to one of my movements. I really have no idea what is going on. All of my other creative worlds that are much, much bigger work and perform just fine. I messed with some of the framerate stuff and chunks but I am not too savvy on that front. My only thought could be the command block. Which I was able to destroy (if memory serves) but nothing happened. The “rose” inside the glass case is still there as well. I am really not sure what to do about fixing it. This is just a last ditch effort on my part. If there is no way then that is okay, but it would suck because I spent a long time on this castle/build.

Thank you for listening.