Running this command was the only thing required for me to get access to the com ports. After that, everything worked perfectly.

sudo usermod -a -G dialout $USER

(note that $USER is part of the command - do not replace that with your actual username)

Try Material Files file manager. It’s the best file manager I’ve used, connects to remote servers, and is open source

https://github.com/zhanghai/MaterialFiles

The best part is it works with Android as well. Whenever I turn my computer on, all my photos on my phone sync to my computer to a folder that gets regularly backed up (using Vorta which is an excellent and easy to use open source backup program for Windows, Linux, and Mac)