Yes, they do.

That driver does not list the 635M but only the desktop version. Which is still impressive but I think they have separate drivers for their mobile chips? The latest driver listed for the 635M is only available for Windows 10 on their website.

Yes, they can. They literally have the correct (legacy) driver in the Ubuntu repo. But the autoinstaller installs the wrong driver during installing the OS. And if you try to manually install it, there is not even a text prompt in the CLI saying “You just installed that driver, do you want to actually use it to? (Y/n)”.

They could have even gone so far as to make a CLI wizard (like many other packages do) or even a GUI wizard. But no, the package just installs and does nothing by default.

Does ubuntu-drivers devices list the correct driver or is the recommended one too new? The driver packages in Ubuntu should install and activate themselves unless you have multiple installed, sounds like you ran into a bug.

Also that is not correct. All the *buntu installers ask you when you install the OS whether you also want to have closed source drivers installed, and then it installs the closed source Nvidia drivers. Just the wrong ones.

That does not change that Nouveau is used by default for the installer itself and by default for the OS if you don't select anything.