Updated command doesn't work

Hello. I got a problem with my datapack. I started making it in 1.20.1 and everything was running how I wanted it, but I wanted to update it to 1.21.3 and it gives no errors but for some reason it still doesn't work. Some functions work, but some aren't so I think it's the commands that are not correct. If someone could help, then I would be really thankful
The pictures are about an item which would give you fire resistance when you wear it. The same commands worked in 1.20.1 but it doesn't work in 1.21.3. Did I write something wrong or missed an important thing?