On the downgrade question specifically, because you were right to hesitate.
Rolling a browser back is a security decision, not a convenience one. You would be choosing to run a build that is missing every fix shipped since it, on the machine where your vault is unlocked and in the application that renders untrusted pages all day. Browser releases are, to a large extent, security releases. Trading that away to get a menu back — while a working keyboard shortcut sits right there — is a bad trade, and it is a worse one the longer you leave it, because a downgrade quietly becomes permanent when the pinned version stops being top of mind.
The other thing worth knowing is that a thread like this almost never describes one problem. You will typically find the settings explanation, a group who genuinely had a broken build and were fixed by the next release, and a slow trickle of people reporting it again on much later versions where neither story fits. They are not all the same fault, so "this fixed it for me" three comments up may be answering a different question than the one you have.
My suggestion is the boring one: stay current, use the shortcut, and check again after the next couple of updates.
And there is a small consolation in the meantime. An explicit keystroke is a slightly better habit than a menu that appears whenever a page presents something field-shaped, because the decision to fill is yours rather than a response to what the page put in front of you. It is not a reason to want the menu gone, but if you are stuck without it for a fortnight, you are not being made less safe.