My DBA has had the same two monitors for a decade and most of the devs just use whatever monitor was on sale.
Technical people are not the people buying Macs. Mac has its place and it hasn’t been technical folks since TPM chips and WSL.
If like to see what you think the “features” are that can’t be replaced. Literally every single feature of a Mac is implemented better with Windows or Windows with WSL. “It’s closer to Linux” No, Linux is closer to Linux and I can’t dual boot or WSL on Apple silicone. “Muh security” TPM is 10x more practical and slightly beats out Enclave in performance. “Muh hardware” if you spend that much money on any laptop it’ll perform well. If you spend that much on a Windows laptop you’d get even better hardware. You could build multiple Linux machines that each outperform the Mac for the same price. “It just works” I have had multiple hours long troubleshooting call with a Jr Engineer that proves otherwise. “Muh package manager” if you struggle with this, you’re not technical. “Muh iOS dev” iOS/Android apps can be tested in a pipeline or through the myriad of tools like Device Farm. Ship it with Fastlane and call it a day. You can handle both app stores this way.
Why do you want a Mac? The only valid choices are aesthetics, brand loyalty or ignorance.
It’s not uncommon to just disable hardware you don’t intent to use. You don’t have to do it mechanically. There’s a lot of kiosks around that have a lot more capabilities than they’re used for.
If you’re looking to do it with a Pi, banana, orange or raspberry, let me know. I’ve spent way too much time finding the perfect screen to use and case to print. I build a rechargeable handheld device that can pull up all my surveillance cameras and functions as a master remote.
You’re thinking about it too hard.
Just use a launcher, sometimes called Kiosk mode/launchers, to launch one app. You can disable the other hardware if you want, but it doesn’t seem like it really helps you reach your goal.
You could probably pull it off with a Pi Zero, battery pack, and screen if you want to get into it a bit. It’s not that hard at all.
There’s no advantage to being Mac like.
You can’t pick the most expensive brands and claim they’re “well rounded”. It’s like buying a luxury car and saying it’s your reliable little daily commuter.
The point is there is no valid reason besides the three reasons I stated for someone to want to buy a Mac. Either you like the looks, the brand or you just don’t know any better and you refuse to learn. Each of those options is valid, but you do have to pick one of them.
What is it about the MacBook Air that makes you feel it is well rounded? Why do you need the compute? Is it for video editing or 3D modeling? Because those run fantastic on midrange hardware now. Are you a developer? Because Mac hasn’t been the developer choice in over two decades. You know what’s better than being Linux like? Being Linux. WSL and the TPM chip removed anything else that might draw a rational consumer to Apple. Do a little gaming? I’ve got bad news about Macs. Lol. There’s no real reason anymore.