Python pyQt5, getting data from a user-entered data file outside of program

Question

I am trying to allow the user of my program to compare two .xlsx files; one of which is already inside the program and is currently broken down and saved as invDict, and the other which will be placed next to the executable by the user. Of course, during testing,i am keeping the program in VSCode so i need to be able to see if my code is working without having to use pyinstaller every time. The file is placed next to my cli.py file, which controls my program which is all in another directory called mainPackage. When the user uses it, it will be placed next to the executable. The code below is inside of the mainPackage, so, when looking for the file, it has to look in the directory above it.

This is my current function:

import pandas as pd
import sys
import os

def compareInv():
    docName = window.SearchBar.text()
    window.InvIncorrect.hide()
    newString = ""
    if docName != "" and docName[-5:] == ".xlsx":
        if getattr(sys, 'frozen', False):
            current_directory = sys._MEIPASS
        else:
            current_directory = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
        file_path = os.path.join(current_directory, docName)
        try:
            surveyFrame = pd.read_excel(file_path)
            surveyDict = {}
            for index, row in surveyFrame.iterrows():
                surveyDict[row[0]] = row[1]
            for key, value in surveyDict:
                if invDict[key] != value:
                    diffAmount = invDict[key] - value
                    newString += key + "is different. Survey value is " + diffAmount + " different\n"
            if newString == "":
                window.InvDisplay.setPlainText("No difference between your survey and previous values")
            else:
                window.InvDisplay.setPlainText(newString)
        except:
            window.InvIncorrect.show()
            window.InvIncorrect.setText("File not found.")

I have not yet been able to get the function to correctly execute, with "File not found" showing every time.

Sorry if this description isn't sufficient, I haven't used stackoverflow before, so if more is required I am happy to provide.