You're being downvote but an appleTV is completely useless without an appleId...

You can set up a Mac or iOS device without ever logging into an Apple account. The only place it is "required" (well, not strictly required , but I guess an iOS device is not that useful otherwise) is for the App Store to get apps (someone correct me on this but I'm not sure you can download free apps without an Apple account, and there's a way, although convoluted IIRC, to create one without entering credit card details)

No. You can give your email and it enables some additional functionality such as iCloud if you want to opt in to that but it’s not required.

When it asks if you have an Apple ID (which can be any email address) there is a skip button in very plain language on a very uncluttered screen where it is very easy to read.

And no, it never asks for a phone number. You are free to add one later though if you choose. But the OS doesn’t want it or use it...

The only place I can think of where you can put in your phone number is the Messages app, which is not even part of the OS.

You would do this on your own initiative by the way, not requested by the app or by the OS. Putting your number into that allows SMS messages to appear on your computer.

Where/when did you encounter that? I used a Mac machine for awhile without even logging into iCloud/Apple ID; I don't recall being asked for any personal info beyond what's required to set-up the machine.

Off-topic, out of curiosity: what distro are you running on the MacBook, and how's that going?

No, I've been using Macs for years and have never created an apple account. They really encourage it, but you can in fact skip all the prompts.