I've never really used it. Just opened Gmail via my browser, no link to Basic HTML any more. Don't see this as an issue. I have one account that I check using Claws Mail. I rarely use the browser interface.
To use Claws Mail with Gmail I had to turn on 2FA in order to create and use an App Password for Claws Mail. This now means anytime I login to Google I need to have my cell phone ready to acknowledge the "Are you trying to sign in?" prompt that is sent to my phone (via internet, not SMS). As long as I keep my browser open I can log out, log in without 2FA. It's annoying but if I want to use Claws Mail, I have to deal with it. I use Firefox. When I am done with the browser, I close it, all history is cleared. The phone on the other hand is always connected.
Supported browsers
https://support.google.com/mail/answer/6557