Zoho works well for me with my own domain (though I am on the old free plan that allows IMAP, while today the free plan only supports webmail or their own app). I also know someone who uses Tuta without problems sending to Google and Microsoft.
Which parts of computer science are you interested in? I would suggest looking at some different universities’ current fields of research to find one with a focus that aligns with your academic profile.
You can use this as a starting point in your search, as it has sorting options based on topic https://edurank.org/cs/eu/
It is a public GPG key (not a Microsoft Publisher file) and while I don’t know, I assume it is used to verify that future updates are from Nvidia and not a malicious third party. It is really common (if not required) to install and trust a new gpg key when adding a new repository in Linux package managers, and done for safety reasons without privacy implications, and I am guessing this is what Nvidia is doing here.
Where do you see any indication that it is used for identification of you/your machine?
I am from Denmark where the biking infrastructure is also pretty good, so I will almost always take the bike if I’m going somewhere that is further than 1 km away (~.6 miles).
But that is just if I’m going somewhere – taking a 4 km walk just for the sake of the walk and getting some fresh air (especially when the weather is nice) is quite normal here.