Beat Saber runs perfectly fine on a standalone Meta Quest, so it is exactly not aimed at the "VR enthusiasts" who would invest a lot of money into PC VR devices like Bigscreen Beyond 2.
It does, but modding the Quest version is notoriously more fussy than modding the PC version is, and the heft of the Quest can get annoying when playing custom maps (most of which are vastly more physically demanding than the stock maps).
Not some of the effects heavy custom beatsaber maps. Also vivify hasn't been ported to quest beatsaber afaik so they're still missing out on all the crazy new maps with custom unity assets and environments.