cool blend of fantasy and deep science-fiction
You forgot grimdark XD So very grimdark. I feel like it's the ridiculous shenanigans of the orcs and the existence of Nurgle (the wholesomeness does not stop it from being thoroughly horrifying) that stops it from being completely and utterly depressing.
buying the models used for the game without intent to ever actually play them
You haven't met many players? XD
There is at least some truth to that. Youngest has been chasing some new box set that he's interested in that came out recently but said that the pre-order was sold out at every discount website he knows about (and some that he didn't until recently) so he's going to have to try to come up with the money for the full price in a hurry (and I think it might be a bit much for him in that space of time). Could just be that everyone over east is buying them up as I don't think there's a huge number of players here (or at least not in our local area, don't know about the rest of the city).
Youngest has told me about the Adepta Sororitas, he referred to them as "Nuns with Guns" (so I guess that's what they're commonly called XD).
I think that Space Marines game that you unfortunately can't play (seems to require some pretty big specs) might be the one that youngest got, I remember him being terribly excited about it and really enjoying it, though he did say that the loading times were quite excessive (he could start it up, walk away to get a drink or a snack and then come back and it might be done or close enough). So probably something to look forward to if you like that kind of thing when you can finally get to a rig that's decent enough to run it (definitely not a MacBook Pro which from memory is what you're rocking at the moment?).
Just as a warning in the unlikely event you weren't already aware, there's a LOT of 40k lore x_x
I have already forgotten more than I ever wanted to know to begin with that's how much there is and how much youngest has been regaling me XD
I don't know if you were ever into roleplaying games but there's also a (pretty old now and doesn't look like it will ever get updates) roleplaying system called Dark Heresy, I kind of vaguely glanced at it as something I could possibly play with youngest seeing as he doesn't like World/Chronicles of Darkness and I don't like Dungeons and Dragons but given Warhammer I'm not sure I'd be able to run it as the last time I tried to run Shadowrun-adjacent (I was testing out a homebrew system in the Shadowrun universe as I've moved a long way away from crunchy systems and Shadowrun 3e was pretty crunchy) I didn't enjoy it which mildly surprised me as I remember loving Shadowrun when I first played it, but I think looking back I just kind of got depressed as it seemed to reflect real life a bit too closely now.
Enjoy your new addiction, at least comics aren't quite as expensive as the models XD