Motherboard’s use a small set of different mounting brackets for CPU coolers. But the physical CPU socket depends on several things including the physical size of the chip and thus the amount of surface area you want in contact with the the cooler.
In case you where unaware actually running a CPU at 100C will drastically lower it’s lifespan. You encounter similar issue if there are significant temperature differences across the chip. Which is why packaging includes a metal plate over the CPU even though it reduces cooling. However, this is a real tradeoff which means the contact area must be reasonably close to design spec.
For example, when introduced there was no aftermarket passive cooling available for the AM4 socket.
Really of the 5 considerations “Does it fit the mounting bracket?” is probably the least important. Fitting the motherboard and case are mandatory. Fitting the socket and TDP have a little wiggle room. However, with mounting brackets you can generally get something to work as long as you keep firm contact and it does not wiggle around it’s fine.
>Lots of closely spaced thin fins actually produce less cooling without good airflow.
That is true, however Noctua coolers tend to have a fairly big gap between fins, because they are designed for very low RPM use.
>In terms of sacrificing performance, let’s agree to avoid the absurd.
Not sure why you think it's absurd - the video just shows that there is no real minimum amount of cooling required anymore, at least with Intel CPUs. Obviously you're going to have to sacrifice some performance if you go passive only.
Although I'm not even sure anymore what we're even talking about. All consumer CPUs use the same sockets. All these coolers are available for every modern consumer or "pro-sumer" platform.