I have noticed for some time (maybe 1-2 months) that updating tokens one after the other slows down Roll20. I noticed this particularly recently when I updated the hp for about 20 tokens during prep. After I loaded into Roll20, opening the settings of first couple of tokens was very responsive, but soon, each one I opened would seem to freeze before I could edit any values, getting longer and longer with each subsequent token. The settings window would appear immediately after I double-clicked the token, it's editing the value that gets delayed. I have seen this issue also occuring when I just update the token radial bubbles when I ran combat and updating hp. The features show up immediately after I click on a token, but I can't edit the bubbles until a bit of time passes. I last tested this today, using Firefox 98.0.2.