Function to generate random string with nested function is giving me trouble

I'm gonna preface this by saying that im quite new to this, dont judge haha. The script im writing is to make a random password from different strings and randomize them. That I have already succeeded in completing, but know that I want to build a GUI for that script, the implementation with functions and tkinter is giving me trouble. I have two functions: One (add2all)that is supposed to check wether a variable is true, and if it is true add it to the string "all", that im later going to randomize with my second function. Im sure there are problems with how I get the value from the Checkbuttons (used to get the user input what kind of characters they want in the password), and then how they are added to the string. My second function (pwdgen) is supposed to get the input length from an Entry box were the user types an int, and then calls the add2all function to see what characters the user wants. add2all should generate a string with all the charracters that have been defined as true, so that pwdgen can randomize them with the given length. I also have a Button that is supposed to start the process. It calls on pwdgen, which then ccalls add2all and at the end, the variable password should have a randomized string which I can display to an entry box.

TL;DR: The function and tkinter implementation of a very simple script I previously wrote isn't working at all.

import random
from tkinter import *
from tkinter import ttk

root = Tk()

upper, lower, nums, syms = False, False, False, False
uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
lowercase = "abcdefghijklmnopqrstuvwxyz"
digits = "1234567890"
symbols = "!§$%&?*+#~-;()/"

all = StringVar()

CheckBool1 = IntVar()
CheckBool2 = IntVar()
CheckBool3 = IntVar()
CheckBool4 = IntVar()
pwlength = IntVar()

#function that checks if a CheckButton input (which characters are wanted in password) 
#is true, if true adds the corresponding character string to the all string
def add2all():
    if CheckBool1:
        upper = True
    if CheckBool2:
        lower = True
    if CheckBool3:
        nums = True
    if CheckBool4:
        syms = True
    if upper:
        all += uppercase
    if lower:
        all += lowercase
    if nums:
        all += digits
    if syms: 
        all += symbols
#function that gets password length from user, then calls add2all, then gives var password
#the string of all randomized with specified length and then puts it into entry box pwdoupt
def pwdgen():
    pwdoutpt.delete(0, END)
    v = amt.get()
    v = pwlength
    add2all()
    password = "".join(random.choices(all, k=pwlength))
    pwdoutpt.insert(0, password)

greet = Label(root, text="Welcome to the interactive password generator!", height=3)

pwdoutpt = Entry(root, width=30)
generate = Button(root, text="Generate", command = lambda: pwdgen())

#inits all the labels and checkbuttons for my gui
chck_1 = Checkbutton(root, width = 5, var = CheckBool1)
chck_2 = Checkbutton(root, width = 5, var = CheckBool2)
chck_3 = Checkbutton(root, width = 5, var = CheckBool3)
chck_4 = Checkbutton(root, width = 5, var = CheckBool4)
lbl_1 = Label(root, text="Capital Letters")
lbl_2 = Label(root, text="Lowercase Letters")
lbl_3 = Label(root, text="Digits")
lbl_4 = Label(root, text="Symbols")
amt = Entry(root, width = 5)
amtlbl = Label(root, text="Num of characters in pwd.")
sep = ttk.Separator(root, orient="horizontal")

greet.grid(column=0, row=0, columnspan=4, pady=3)
pwdoutpt.grid(column=0, row=7, columnspan=4, padx=30, sticky=W)
amt.grid(column=0, row=1, sticky=W)
amtlbl.grid(column=1, row=1, columnspan=1, sticky=E)

chck_1.grid(column=0, row=2, sticky=E)
chck_2.grid(column=0, row=3, sticky=E)
chck_3.grid(column=0, row=4, sticky=E)
chck_4.grid(column=0, row=5, sticky=E)

lbl_1.grid(column=1, row=2, columnspan=1, sticky=W)
lbl_2.grid(column=1, row=3, columnspan=1, sticky=W)
lbl_3.grid(column=1, row=4, columnspan=1, sticky=W)
lbl_4.grid(column=1, row=5, columnspan=1, sticky=W)
sep.grid(column=0, columnspan=10, row=6, sticky=EW)
generate.grid(column=2, row=7)


root.mainloop()