EV3 Folder not appearing on Windows
This is from https://makecode.mindstorms.com/troubleshoot
Check that you have the newest firmware; on the EV3 brick:

Go all the way to the right to the wrench tab

Go all the way down to the menu called 'Brick Info'

The information dialog that appears should say something like:
Brick FW: v1.10E


If you have a version which is less than this, then you need to upgrade. Unfortunately, this can only be done from the very buggy EV3 Manager at https://ev3manager.education.lego.com/