Hi @TSilverCat1 ,so sorry for the delay ,
it looks the same problem as above so sudo pacman -Sy blackarch-keyring
can fix it .
please try the first one then this if it didn’t work :
→ gpg --recv-keys --keyserver hkp://pgp.mit.edu 4345771566D76038C7FEB43863A615AD0C2C8548
→ then : gpg --edit-key 4345771566D76038C7FEB43863A615AD0C2C8548
→ at the end : sudo pacman -Syyu