In case it helps, I have the same problem. Running python 3.8.8 on Windows 10, and any MWE doesn't work, e.g.:

from tkinter import filedialog
from tkinter import *

root = Tk()
root.filename =  filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = (("jpeg files","*.jpg"),("all files","*.*")))
print (root.filename)

I just get the spinning circle and unresponsive dialog. I have quite a few shell integrations so uninstalling them is not ideal.