Find files with multiple matches of a pattern in the filename in linux [duplicate]

I'm trying to find multiple files with 40 hexadecimal digits. I can use

ls -l | grep '[0-9A-F]\{40\}' 

And see the files I want to see them but I want to use find for this for the sake of the challenge. I tried:

find . -regextype grep -regex '[0-9A-F]\{40\}' 

It doesn't work. I would be happy to understand this matter.

Bonus question: How this can be done with shell regular expressions like this: ls -l [0-9A-F]{40}?