HLS is, indeed, in the mockup and systems testing stage in parallel:
And there have been references I'm not quite sure how to find now (loose tweets from conferences) of other mockups at Hawthorne, being worked on with NASA, the dev crew displays mentioned have been seen at some point in the past year (very similar to Dragon), and the lift for lunar access was being prototyped/mocked up last year. It's almost certain the whole system will take longer than we'd all like and the challenges aren't trivial (though one can't expect miracles when the lander was only selected in 2021 and "oh btw, for 2025 please thank you"), but they're not sitting doing nothing while the flight tests move forward. And regarding the whole thing about how many launches, the estimates we've been getting from different NASA personnel this year alone have varied from high single digits to high teens, I think there's still a lot of water needs to flow under the bridge before performance stabilises and a more precise number is determined.
I will say, I don't think it was the right choice for the first landing. They were going to work on a lot of this anyway, but it's overkill in capacity and there are many unknowns to put the pressure of a first landing date on. I'd be happy to see the BO option pick up the slack if NASA get tired of waiting, it seems like a more reasonable approach for the first steps, though it's worth noting they also rely on orbital propellant transfer and have boil off to deal with, and New Glenn still unflown. Then, if we get as far as needing higher cargo on the surface for more extended stays, Starship would have hopefully matured enough by then. On the up side, NASA is investing in new technology which, even if it makes for a crap lunar program, will end up benefiting spaceflight in the long run, hopefully.