[fireattack]

Oh God, after reading your post, it suddenly struck me that maybe I should try using a different Google account, even though I don't really have anything special in my main account.

I registered a new account, and voilà, it suddenly worked!

I compared all the options and couldn't find anything that would cause this until I discovered that my main account's Tools > Accessibility Settings had "Turn on screen reader support" enabled, for which I have no idea why.

I turned it back off, and the issue immediately disappeared.

To be fair, I think enabling this accessibility option shouldn't cause such a bug; but for now, I can finally use it again.

Again, thank you for taking the time to test it!