I have around 100 fairly small notes with couple larger PDF and image attachments in a separate folder, and I reshuffled the notes in to a PARA folder structure. I then discovered that opening notes was taking a while, maybe a second. The title would change but the content would lag behind. Restarting Obsidian didn’t help. This issue persisted a day until I looked in to settings and gave a wild guess that clearing File Recovery core plugin cache might help and it did.
I was able to reproduce this with a folder rename (containing notes only, not attachments), though not reliably, some notes would be sluggish to open. I disabled the file recovery plugin and I’m not seeing any sluggishness now.
I’m not really looking for a solution for myself, just letting you know that this happened. Version 1.5.3 (Installer 1.4.14).