How can I use a MacBook Air as a screen and Mac mini pro as a computer?

If you're really worried about throttling, at home you could put the MBA on a cooling pad. Naturally that only makes sense if otherwise it's fast enough for you. Perhaps just get the MBP, based on your reply to another commenter. In any case, a couple of pounds are not worth the hassle of having two machines. Do consider offloading some work to the cloud.

I wouldn't set your hopes that high. It won't manifest CUDA or Vulkan drivers for you magically, nor extend your battery life by having more cores and a larger screen.

You're ultimately looking at a set of tradeoffs. There are a lot of options, but none of them are really perfect. If Macbooks are my only option, I would probably be content with a Macbook Air with a high enough memory config. If you really need that much more power, you could purchase a separate Mac for home and VNC/SSH into it when you need the extra power.

There is no silver bullet here. I would reconsider how much power you actually need though; even the most intensive programming jobs can fit comfortably on a regular multi-core processor.

I also have spinal issues and can’t carry too much weight. I find only a 14” MBP + iPad, even without chargers and accessories, in my backpack to be heavier than what I can handle.

Just buy an MBA for the road, and another computer (Mac/PC) and a proper display for home/office use.

Per the Advanced... screen under Displays in System Settings, you can link to a Mac or iPad to control it a la Synergy[0]

I have not done it myself, but I do not see why you could not do it with a current-gen Mac Mini

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[0] https://symless.com/synergy

Firstly, in no way and hell 2 lb difference between MBA and MPB is going to matter for comfort when carrying in a backpack.

Secondly, MBP is decent in processing for a laptop, but it absolutely is shit compared to what even a mid grade desktop with desktop cards can put out.

If you actually want to have processing power on tap (for ML I assume) you need to build a desktop with a few gfx cards and a good desktop chip, and then set up ssh to it. Then you can use literally any computer or even your phone to run models.

On the flip side, if you are trying to find reasons to get a Mac, just get whatever Mac looks the best to you and stop pretending you need processing power.