Wanna switch phones? lol

You’re right, what my brain saw was

The default setting is now the desktop version

what it actually said was:

Firefox and Opera both allow you to view desktop sites in the same way as Chrome. Find the website you wish to visit and open the required app. From the menu on the top right corner, tap the three dots to request a desktop site on Android.
The default setting is now the desktop version. If you wish to change it, just reverse the steps above.

So ignore that part lol

It still implies that once I’ve switched it on, it should stay on though, which it isn’t, so the question remains