Boot your Pi from USB and there is no SD corruption to worry about. This has been out of beta and officially supported for over 2 years now. I've never had an issue with power adapter compatibility but understand some had issues when the RPi 4 was released due to it requiring more amperage than previous models. Not really a concern with modern USB C adapters and if you are really concerned just buy the official power supply or one of the multitudes sold on Amazon as for the RPi.

As for overheating, I have had a RPi 4 stuffed in a crowded wiring box with no air flow in my unconditioned garage running non-stop without overheating for a few years now. I live in a climate where it is over 90 degrees Fahrenheit every day June - early September with a good part of late July - late August being over 100. I also have a 4 node RPi cluster which has been running for years without any overheating issues. The cluster nodes do have 5v fans running at 3.3v to reduce noise. I installed these when originally setting up the cluster but would be confident removing them. At this point it just isn't worth the effort to do so.

That'd be ideal replacements. Similar spec to SBCs with a touchscreen and battery backup. But WiFi not ethernet.

Rpilocator tracks stock and has found some sites stick things regularly once a week but if you don't buy within 10-20 minutes of the in stock alert, you'll miss it.

Even Upton said he thinks the supply will be getting better to the point it'll be fully stocked again within one year.