Just about every resource I've found is outdated, or no longer available. Is there a currently maintained Linux hardware compatibility list?

I can't just walk into a Best Buy and plug in a live USB. I've been pretty lucky so far, having bought new, but not necessarily bleeding edge tech, and having it pretty much work with Linux.

in general the new hardware is not really usable as long as the drivers are not available for that. So you need to check if these are supported. Sometimes easy, sometimes not.

https://linux-hardware.org/ does not look outdated at all...
You can find parts and computer probes, that others did for you.
Let me know if this suits your needs.

There's simply too much hardware and too many implementations of Linux for that to be feasible (anymore).

It usually goes like this:
New hardware comes out, it takes a few months until development picks up on innovation inside the components, and the first distros start shipping the updated OS software.
So you'd constantly have devices slipping out of the blacklist and into the whitelist.
There might be a few devices (or rather components) that Linux has difficulties with even after, say, 1 year.
So if anything, a blacklist would make more sense.

Here's my personal solution:

• never buy anything that "just came out"
• Linux-specific research before purchase

That said, plenty such lists exist, as already pointed out. Also many distros have their own. E.g. https://wiki.archlinux.org/title/Category:Hardware - or Ubuntu I believe even makes a business out of that. "Certified devices" iirc.

You can buy basically any hardware, if you follow a few rules

1. With new AMD stuff, be prepared to be a crash tester.
2. Grab pc specs (harder to come by these days).
3. For any suspect part, try to download a driver.

Ideally, you won't be able to download, as the driver & firmware is in the kernel. On some things, (e.g. Realtek's wifi cards, Mediatek/Ralink drivers), you will get an 'out of tree' driver, and in that case, YMMV.

Generally, the more esoteric your peripheral, the less likely support is. But standards are your salvation.

Also, web search for "[make/model/item] linux" will often turn up helpful links.