This is what rquickshare documentation says: "Wi-Fi LAN only. Your devices need to be on the same network for this app to work." So no, it's not an AirDrop replacement.
I don’t think this article is actually accurate. It seems like Google just reverse engineered airdrop rather than Apple changing the tech they use. Because quickshare works with all airdrop devices now. Not just ones recently updated.
it's widely expected Apple will find some way to lock it out
I suppose that is "widely expected" from the usual group of anti-Apple internet griefers looking for a reason to moan in public, rather than actually doing some research or knowing things.
To quote a sibling comment:
"Apple contributed the core logic to the Wi-Fi Alliance to build Wi-Fi Aware, which they now also support."
Not generally, I just don't have that specific phone that has implemented the workaround, and so this isn't a solution for me.
Apple has consistently done everything it can to self-sabotage their implementations of stuff to comply with EU anti-trust legislation like the stuff with digital marketplaces, so I'm not holding my breath on this.
With Linux it's very easy as long as you're okay going offline - just make an ad hoc wifi network, have the other device connect to it, then you can do whatever (Localsend, host a local webserver on the linux machine, whatever.)