One Page Rule's Grimdark Future Firefight literally just not 40k You can even use your 40k models almost 1:1 conversion. Also they don't care if you 3d print your own models.
Mantic's (founded by former GW people) Kings of War basically improved on classic Warhammer Fantasy, even has its own lore that people fallow.
Warlord Game's (also founded by former GW people) history based Black Powder, A wargame with models and settings based off of military history. If you want to see Oliver Cromwell's New Model Army vs Otto Von Bismark's Prussian Army this is the wargame for you.
3D printing is always an option too just don't give GW your money but still keep the fire on them though. They need us we don't need them.
Regardless of how many youtube channels constantly mention One Page Rules, no one plays it. I've seen people try to play it, maybe a couple of friends who are both irritated by GW because of something they did that particular week give it a try, and then never touch it again.
I've heard Kings of War has(or at least had) a following in Europe. Never seen that following in the US.
Black Powder? Bolt Action I've seen sold and played in stores. Hell, I've seen events for it. There's a reason why someone thought that World of Tanks f2p grind fest could make for a miniatures game IP. But Black Powder? Again, it's one of those maybe someone can get a game in once a year type of things.
Hell, you're more likely to be able to find a game for Marvel Crisis Protocol, Star Wars Legion, or Shatterpoint than any of what you just listed and look at how Disney has been treating those IPs for the past decade. A Song of Ice and Fire has a decent following if you're into that. Conquest and Infinity I've also seen people host successful events for, so those also have a draw. I'd put Battletech on the "could find a game if you asked around enough" list as well.
At least you didn't bother trying to bring up completely dead games(malifaux, warmahordes, xwing, etc.). Don't get me wrong, I would like for there to be more games to play, and GW doesn't need to occupy 80% of the market while the rest fight over the scraps. More variety is a good thing.
3d printing is an option, but it's still a hobby of its own on top of the existing miniature wargames hobby. It's still not ready for prime time. If it ever gets to the point of opening a box, adding a bottle of resin, and hitting a button to just go, with no fiddly bullshit calibration, failed prints being a rarity, resin that isn't going to give me cancer because I looked at it funny but need to buy a fucking wash and cure appliance that might as well be another dishwasher, etc. then 3d printing absolutely will take off giving GW and some of these other companies something to worry about. But we're still a few years from that point.
