Firefox mobile did the same kind of stuff... They disabled most extensions, there is only about 15 left... I still have Firefox Mobile v68 installed for this reason.
my password manager makes the login process pretty fluid... but either way, incognito is not regular browsing... it is supposed to forget cookies and such tracking mechanism.
I think that Mozilla are trying to make addons disappear.... they started with Firefox Mobile, only about 10-15 addons are available now (which is why I use an ancient version of Firefox Mobile).
They are getting a lot of money from Google, so it MIGHT be a request from Google.
