7 Days to Die? Not exactly new, but it has finally left Alpha lol. It's voxel based, zombie killing, post apocalyptical with base building in it. Might be worth a go!
7DTD hasn't left alpha. The devs just relabelled alpha 22 as 1.0 to make it easier to sell on console and to "justify" doubling the price. It's still in alpha. It's still labelled as being in alpha on the loading screen, with the same message about it being in development and that it might not work and that it might crash. It's absolutely definitely still in alpha.
That said, I still think it's a very good game and a very good match for what the OP wants, especially with the thousands of mods available for it. Some of the mods are specifically for base building. Alpha 1.3 (the current version) is stable and the only things missing are a story (which isn't a big deal in this type of game), human factions with ranged weapons (also not a big deal in this kind of game) and the outside temperature affecting the player character (that was removed in alpha 1.0 for some reason and is supposed to make a return in alpha 2.0 some time this year). It's also a flat cost. There is no DLC. Not yet, anyway. None of the DLC would be as good as the mods, anyway.
Part of the edge it has regarding base building in particular is that the entire world is malleable. You want to dig a cave base inside a mountain? You can. You want to dig a leat so that a river will fill a moat around your base? You can. You want to rebuild a partially collapsed building to use as your base? You can. There's not much you can't do with the world. You want to demolish a skyscraper? You can. Level a large area to build a huge base? You can. You want to build anywhere, any size? You can, except for areas very close to traders. You want to build a nice tarmac road from your base to a trader, tunneling through mountains and spanning ravines? You can. Etc, etc. I once built a giant pyramid with its own power station to run the silly amount of lights on it. Why? To advertise a trader because the idea popped into my head.
You want a horde of zombies to attack your base every night? Every x nights? On random nights? Never? All of the above are options.
I've played 7DTD for ~2500 hours over the years. I'm not bored of it yet. However, that's because of mods. Vanilla 7DTD doesn't have that amount of duration.
As for "hardcore" and time consuming, that depends on what settings you choose and what mods you install. Vanilla on the lowest difficulty setting and with blood moon hordes turned off is relatively gentle. Some of the overhaul mods are extreme even on the lowest difficulty setting. Some of the overhaul mods are much more time consuming. For example, the overhaul I'm currently playing ("Craft Until You Die") places a far higher emphasis on scavenging and crafting and it's very time consuming because of that. You'll be spending a lot of time mining, farming, dismantling gameworld items for components and crafting.
There are mods that enable taking items from the gameworld to decorate your base. There are mods that add far more stuff to build for decorating your base.
Even vanilla, I think it would be a good match for what the OP wants. With the right mods, I think it would be a superb match for what the OP wants.
