Pretty sure most everyone is accepting LD as canon in the tighter sense of "in continuity with the other series". That's the view of Mike McMahon, Alex Kurtzman, the "Star Trek Universe" team at large, and appears to be the view of CBS Paramount. The view of the few fans who discount LD (and TAS) for silly reasons will only go away further as the producers and production consistently place it within continuity of the live-action shows.
We don't need to see Boimler and Mariner or even hear of their exploits in Star Trek: Picard to accept that what they are doing in 2380 is a historical fact in the latter series. Given the wiki Memory Alpha's prevalence as a source and compilation of these facts, and its uncontested view that Lower Decks is in continuity with all other aired Trek, more casual fans will continue to accept it as happening in this world, and this will spiral into future creators down the road and the view that LD is not canon will become more and more harder to defend in the coming years.
I'd have to agree, especially in regards to the argument that TAS isn't canon. There could be an entire academic journal dedicated to arguing the canonical status of various mediums of Star Trek. I have always prescribed to a rather simplistic perspective on the matter - the officially produced movies and shows are canon, everything else is not. That isn't to say I don't love a good comic book or novel, in fact just the opposite. Where I draw the line in the canon argument is when we start debating which episodes or movies are considered canon. At that point we are simply picking teeth over a rather subjective discussion.
In regards to a live action LDS in particular, I don't feel it is needed. I'm no writer, but the tone and atmosphere of the show doesn't feel like it would immediately translate well to a live action medium. It'd be forced, in my opinion.