Interestingly, the M2 Mac Mini has TB4 and supports two connected displays, because there isn't an internal one. Yes, it's still 2 total displays, but it's the only non-Pro Apple Silicon machine with TB4 instead of TB3. I'm not sure if the only real distinction is allowing a second monitor on the link, or if there is additional bandwidth as well.
The Thunderbolt specs define minimum quantities of connectable external displays. Thunderbolt 3 requires support for 1+ connected displays, Thunderbolt 4 for 2+. Apple creates an artificial restriction for profit reasons, and does not equip MBA with Thunderbolt 4 as a result.
MacBook Air uses Thunderbolt 3, which only requires 1 additional display. Thunderbolt 4, which the MacBook Pro 14/16 has, requires support for connecting at least two additional displays. [0]
If you would like to achieve this based on simple dimming, or even better, by using smart switches instead of smart bulbs, take a look at NASA spinoff Bios Lighting.
In (iOS && iPhone<9), you can toggle this filter with the triple click trick. In Settings > General > Accessibility > Accessibility Shortcut, select Color Filters, then triple click the home button.
I would trade my smartphone in an instant for a dumb phone with a great camera, 3.5mm audio port, and LTE/WiFi for tethering. The closest thing out there right now is the LG Exalt LTE.