If you write /Haz{4,}zah/ it means at least 5 ‘z’ (the 4 from the z{4,} and then the one after that), it is different from /Haz{4,}ah/ where it is at least 4 ‘z’, one less because you don’t have the ‘z’ after the parenthesis
Though i have the doubt if /Haz{4,}zah/; will work because z{4,} match 4 or more ‘z’, and the following one could already be matched so there would be an ‘a’ after the 4 or more ‘z’ but the expression wants a ‘z’ after the 4+ z, so I am not sure this would match… regex is strange to me still