I love a great epic storyline, huge open world. Nitpicking but I like to have a lot of customization over my character as well. So games like the Elder Scrolls series, Dragon Age, Fallout, a neat game called mount and blade, have been a blast for me. I fall victim to over playing. I sunk so so many hours into Skyrim remastered just to drop it suddenly.
Mass Effect has the same Devs as Dragon Age doesn't it? I'll continue to watch some gameplay videos and make a decision. Gutted there isn't a Red Dead remaster for the new consoles.
Seeing as you're clearly into rpgs I think you'd be fine with Nier, though it has more of an idiosyncratic, Japanese flavour than most you've listed there. The physical world is smaller than Horizon which is pretty sizeable, but there's actually more content in Nier in terms of sidequests and an epic sprawling story. Really nothing touches Nier story wise here, and I found the horizon story to be much more by the numbers. That said the actual universe of horizon and the lore around it is really good, so that kept me captivated, just not half as much as Nier's epic story which incorporates dark, existential themes and utilises clever fourth wall breaking at times to genuinely make you think and feel. If you can get to the proper ending without shedding a tear (both of sadness and of joy) then you're a monster.
As for customisation neither has proper character editing, you play as fixed protagonists (though there are 3 in Nier) but both have your standard equipment fare. However Nier does have one incredibly cool feature which is the chip system. As you play as an android, they have memory. As in storage space. You can have up to 128 slots to fill in with whatever you want, though hilariously 2 are used for your operating system (don't remove this unless you save beforehand, ha). The rest you can use for your ui elements or speed boosts, various combat effects which might slow time, make you hit harder, heal when you kill something etc. There are chips for more item drops or more experience. It's just really novel and never before have I ended up removing a ui element to make space so I can make my character stronger.
However as
@ijjysmith says, Horizon is not niche. It is good at everything and has a bit of everything so if you want a safe bet then go for it. But I would say if that if you do enjoy Nier you'll utterly adore it, more than horizon. More than most games you've played. But equally there's more chance you might not enjoy it! Play it safe or take more of a gamble, it's up to you!
As for mass effect, though I have it pre ordered and love the series, I'd hold off. Early previews aren't great and though that isn't damning, it's not positive. Whereas Nier and Horizon are both out and are both critically acclaimed and loved by players too.
