Vibrant Visuals won’t turn on in new 26.40 update

Ever since this 26.40 update in the Minecraft Bedrock edition, the vibrant visuals are grayed out whenever I open an existing world, before this update it worked on all my existing worlds but now not anymore, but whenever I open a new world, it isn’t grayed out and the vibrant visuals are accessible. I have tried many different methods to get it to work again and it won’t. Is there a way you guys can fix this issue with a new patch? Also I don’t have the new items that were promised in this update either unless I set it to experimental mode.