SECOND UPDATE NOTICE: the problem of the world crashing still remains. I am unsure if it's the texture pack I'm using or some other unknown issue. again I'm using hattoricraft texture pack.  

UPDATE NOTICE: the problem appears to have been solved. however it constantly crashes making it unplayable still. I am using hattoricraft texture pack but i have no problems loading my only two other worlds with the pack. 

This had been going on for sometime actually well before the 1.16.20 update. some time ago i had bought the the village of turtle island by BTWN studios combined world/skin pack and after several complaints about the issue and trying everything I've been told to do it still won't work fully. I can access the skins but not the world. It shows up in my packs list but instead of saying owned or download it shows the amount of Minecraft coins it takes to purchase it. I was told in the latest email sent that i should contact the developer directly but when i look there's no button so i can't contact.  I have added a picture showing the glitched textured pack.