What is needed is to validate from a given string, if the user when typing his password has repeated any of the valid characters more than twice and in the case that he has not done so, the password should not be matched because it is not valid.
I have tried with this
(?!.*([a-zA-Z0-9@._\-\/,])\1{2})
and this
(?!([a-zA-Z0-9@._\-\/,])\1{2})
This regex will try to match the entire string, start to finish, without any character repeating 3 times (immediately after each other):
^((?!([a-zA-Z0-9@._\-\/,])\2{2}).)*$
https://regex101.com/r/ci8hMK/1
If a character is not allowed to appear more than 2 times in total:
^((?!([a-zA-Z0-9@._\-\/,]).*\2.*\2).)*$