Single player worlds with more than about 3 add ons active will not load and error message occurs, Before the 1.21.130 update today it was working fine with 20+ add ons on a world

Since the mounts of mayhem update i have been unable to load into any minecraft world that has over 3 add ons activated. My pre existing worlds all have around 20-30 add ons active at a time and work perfectly fine however since the recent update every time I try load into my worlds it crashes and has the error message "block" appear. Im really hoping you fix this because I just cannot play minecraft without a large amount if add ons. Definitely an issue with the amount of add ons rather than a specific add on because no matter what add ons I used or didnt use the game still crashed when trying to join modded worlds. Im assuming that that means my worlds are now lost forever because last time u guys updated loads of people lost their worlds. Ive seen a lot of other players having this issue to, honestly game breaking for a lot of players. Thanks, hope i explained the issue clearly