I CAN flash using the following from the command line:
/M5Burner_Linux/packages/tools$ python3 esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 750000 --before default_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size detect 0x1000 /home/david/Desktop/m5stack/M5Burner_Linux/packages/fw/atom/UIFlow_Matrix-v1.7.2.bin

I can then connect in UIFlow if I hold the button on the Atom while plugging into USB.

However, I still cannot get the M5Burner App to work. I still get the Javascript error when I click the Configruation Button.

If I perform the following from the command line:
M5Burner_Linux/packages/tools$ python3 esptool.py erase_flash

I am able to erase flash. However, if I simply run
$esptool erase_flash

I get an error saying:
A fatal error occurred: ESP32 ROM does not support function erase_flash.

My installed version esptool was 2.8 but the version in the M5Burner.zip appears to be 2.5.0. Is there maybe some issue with version 2.8 of esptool? The 2.8 version is what is installed if apt-get instal esptool is used.

I tried using pip3 install esptool
This has installed esptool v3.0 into
~/.local/lib/python3.8/site-packages

From this folder I can run python3 esptool.py erase_flash and it was able to erase the flash from the command line using the V3.0 esptool.

I ran the following to remove esptool v2.8:
sudo apt autoremove esptool

However, I am still getting the Javscript error when I click the Erase flash button inside the M5Burner App.

I have tried downloading the MACOS version from the FlowUI as I saw the Linux Instructions said to do this (at https://github.com/m5stack/m5-docs/blob/master/docs/en/related_documents/how_to_burn_firmware.md). However, I do not see any folder called firmware within the Resources. If I do a search there no flash.sh file.

@ajb2k3 Thank you for responding.

Here is the additional information you requested:

OS is Linux Mint Version 20.1 / Ulyssa (based on Ubuntu 20.04) - kernel 5.4.0-65

I just tried the following again:
Downloaded new version of M5Burner_Linux.zip
Extracted to ~/Desktop/m5stack/M5Burner_Linux
cd ~/Desktop/m5stack/M5Burner_Linux
run the command ./M5Burner

M5Burner app opens
Select COM: /dev/ttyUSB0
Baudrate: 75000 (M5 Atom connected)
Select ATOM on the left-hand side of the window
Click the Download firmware button for the UIFLOW(MATRIX)
Download Completes successfully

Select Erase Flash
Then I get the JavaScript Error Message

Select the Configuration Button
Then I get the same JavaScript Error Message

What device are you using?
M5Stack Gray (purchae date 1/14/2021) and Atom Matrix

What firmware are you using? how did you burn the firmware into the device?
version 1.7.2

Version of UIFlow you are using
M5Burner Version 2.2.7
UIFlow Version 1.0.14

PROBLEM 1:
Whenever I click the configuration button in M5Burner, I get the attached error message.

PROBLEM 2:
(this is less of an issue than problem 1) the M5Burner screen will not resize property to my laptop resolution (which is only 1366x768) the minimum width appears to be greater than 1366.