Resource for converting from older version to 1.21

I have a datapack we used to use on our server called Custom Archeology which allows one to throw an item on the ground, cover it with a sand block, and it would convert the item into a block of suspicious sand with that item inside. It has not been updated to 1.21, so I am taking a stab at it. Things I have done: Update the datapack version in the .mcpack file, and rename the folder structures from plural to singular. I have also tried running a lot of the code manually in game via commands to try and find the lines that might be broken. I know Mojang overhauled a lot with the recent update, and changed a lot of item things to components. Are there any guides for converting from older code into the newer formats that people are aware of yet? If not, are there any guides that have been put out for foundational .mcfunction and datapack work for 1.21? I have tried to parse the Minecraft wiki, but it's unfortunately still a little above my head. Thank you I believe the errors to be specifically in the bugfix:item_macro_tag.mcfunction bugfix:item_macro.mcfunction customsus:set_gravel.mcfunction customsus:set_sand.mcfunction