Do I need to worry about Activation Lock on a brand new Macbook that's never been connected to the internet?

First, I need to correct my earlier statement, which is backwards. For at least the past few OS releases, what you can't do with a beta release is install it on a blank partition. Only over an existing one. Though I've never tested how installing a beta OS behaves from a USB drive.

I didn't address Activation Lock because your post doesn't really have anything to do with it. By not registering your new Mac, it won't appear under your Apple ID. Since it's not there, you can't apply activation lock to your Air if it's ever lost or stolen. Which you already know when you stated someone could steal it and have a new computer.

Here's the part I don't understand:

because I do not wish to be dependent upon Apple to authenticate me when I do whatever I wish with my computer.

Where did you get that idea? Apple doesn't care what you do with your computer whether it's associated with your Apple ID or not. Our Macs boot up every day without ever asking for some sort of authentication before it will go to the desktop. And that's because we have automatic login turned on. If it's off, the only thing the Mac would ask for is the user account password you gave it. Which has nothing at all to do with your Apple ID or activation lock.

Regardless of all of that, I would still strongly suggest you not install Ventura until it is officially released. Betas do not behave the same way the official release will.

Are you saying that no activation is required on this MacBook unless the user has explicitly enabled it?

I should be able to buy a new laptop, install Linux on it, zero over the hard-drive or whatever random crap I want to do, and then recover it. All without involving activation from Microsoft, Apple, or anyone.

If you want, sure. People do it all the time, though sometimes not deliberately. Windows in particular when the user just wanted to set up a Boot Camp partition and instead managed to turn the entire drive over to Windows, wiping out the Mac OS in the process.

Others on this forum noted they've purchased Macs expressly to wipe and run Linux on it simply because they believe Apple has better hardware and have no intention of ever using Apple's OS.

I'm not sure how either is possible on an Apple Silicon Mac, though. Windows only has an ARM version for developer testing. It's not available to the public at all, and MS has said there will never by an ARM version of Windows for sale. No idea if there's an ARM release of Linux.

As far as "recover it", depends on what you mean. If you don't create backups of your personal data and the drive dies, then you of course aren't going to be able to recover much of anything. If you mean can you wipe the drive and get macOS back on it, yes you can do that any time by booting into recovery mode.

I've never had to "activate" any Mac I've owned. But then, I also have yet to purchase a Mac using Apple's own CPU. So I have no experience there to say whether or not an Apple Silicon Mac has the same type of activation an iPad or iPhone does, or what it even does. Doing a quick search just now suggests you do. One person gave the steps to reactivate an M1, M2 Mac if it was reset:

1. Power off your Mac.
2. Hold Power Button until you see "Loading startup options", Then click options.
3. Wait for it to boot, then select your Language (if applicable)
4. Find the Wi-Fi menu in the top and connect to your network.
5. Activate your Mac.
6. Reboot, and follow the instructions. This time, you should be connected to Wi-Fi.

It's asking to erase the entire volume because Ventura is in beta. It will not install over an existing OS.

I would strongly suggest you do not install Ventura until it's officially released in the fall.

Since you wish to install a beta, all other questions are mute. We are not allowed to discuss anything beta related because it will violate your NDA. If it is the public beta, there are no discussion boards for you to seek help. And if you have signed up for betas, you need to follow Apple's instructions to install it.

Ah, there's the confusion. Device activation vs. Activation Lock.

I really don't know why Apple has the device activation thing for iPads, iPhones and now apparently, also Apple Silicon Macs. What's the purpose?

Activation Lock is a completely different thing. It allows you to remotely lock or erase a stolen or lost device.

Because I was curious (again) to find out why devices have activation restrictions, I finally found out. It's this:

Apple does this to prevent people from having free unlimited storage.

What users could otherwise do is create account after account for the same device, all of which would have the default free 5 GB of iCloud storage space.

Unfortunately, this also works against users who are honestly selling the device down the line. Sold for the third time, that person (fourth owner) would not be able to create their own user ID for that device since the three new account limit had already been hit. So there they are, stuck with an otherwise perfectly usable device that has nothing wrong with it, but can no longer have another new account created for it.

Happens all the time. I was looking for an inflatable two person pedal boat yesterday (if there is such a thing), and Google kept returning two seat paddle kayaks.