Nice solution, it's compact and simple to understand. There is little to improve, few suggestions:

• Imports: there are a lot of imports, maybe leftovers of previous attempts.
• Try Except block: should be around the code that can cause the exception.

Applying the suggestions:

import re

class Solution:
    def myAtoi(self, s: str) -> int:
        MAX, MIN = 2147483647, -2147483648
        s = re.findall(r'^\s*[+-]?\d+', s)
        try:
            res = int(''.join(s))
        except:
            return 0
        if res > MAX:
            return MAX
        if res < MIN:
            return MIN
        return res

Performance

Runtime: 36 ms, faster than 51.56% of Python3 online submissions
Memory Usage: 14.1 MB, less than 32.27% of Python3 online submissions

Regex makes the code compact but is not the fastest approach. Faster solutions iterate through the string character by character.