I'm not sure you really understand how much work game dev is. I have a degree in game dev, and still have only scratched the surface of what it really takes to make a game using a real engine like Unreal or Unity.
To use Unreal, you're going to have to know how at least some C++. Even if you're using Unreal instead of DAZ, you're going to have to spend a lot of time animating too. You may not have to wait for render times, but a game rendering in real time is always going to look worse than one pre-rendered and things don't just magically work. They generally need to be adjusted and coded to properly play at the right times. You'll also need arguably more time in Unreal because you have to keep in mind things like how the animations will affect the frame rate and adjust. You can't always just straight port and have things work the way you want. It's almost always more complicated than that. Home Together looks great, but still not as good as a high quality DAZ or Blender animations. There's also the problem that if you're going with a game that renders in real time, you're going to severely limit your audience. Since only people with good enough hardware will be able to play your game.
It should also be mentioned that Home Together is that dev's second game. They already had a successful first game and had the funding and experience to do a lot more with their second. They are clearly a team of professionals. Even their first game shows that they already had experience in game dev. So unless you're a professional game developer already, you're not going to be able to get to the same level of quality as Home Together. Unless you have tens of thousands of dollars just lying around so that you can hire professionals to make the game for you. Even then, it would be a way better investment to make a normal game. You have a significantly larger audience and you'll make way more money that way.
I'm not saying you shouldn't make a game or anything, but you should keep your expectations more realistic. Try to really think things through before deciding what to do and keep in mind that you're just one person. The biggest adult games are teams of people.
So while you can use Unreal and put in the work to actually learn it and put out a game that renders in real time, but you should also keep in mind all of the drawbacks. The limited audience, the steep learning curve, the lower quality visuals, having to pay for a license, etc. There's a reason that there's so few games that use Unreal, and a ton use DAZ with Renpy. Renpy is very easy to use, simple to learn, and is free. There's also other easy to use game engines you can use instead of Renpy if you don't want a visual novel, like RPG Maker. Even Unity is a bigger game engine that's easier to use than Unreal. Although in school, our first game was to make a visual novel, because they're the easiest kind of game to make. Making one is very fast compared to other kinds of game development too. There's a reason that it takes teams of 30+ people 3+ years to make a game. It is incredibly complicated.
Then in terms of visuals, DAZ is very easy to learn, is generally less time consuming since you can buy literally everything, and generally looks better. Yeah, it can take a while to render out an animation in DAZ, but you can easily speed up that process by doing things like oversampling, using a render farm, or just upgrading your PC.
Also, while Home Together might use DAZ models as a base, I wouldn't be surprised if they modified them. At the very least, the animations are clearly custom. They're also very well done and were done by someone who is very clearly incredibly experienced. The facial animation alone gives that away. Facial animation is the hardest kind of animation to do. It also wouldn't surprise me if they had a motion capture setup. Unless you're already a professional animator, you're not going to be able to do anything anywhere near that quality. Even with a game dev degree with about a quarter of my classes being 3D animation focused, even I'm not anywhere near what they're doing.
No matter what, your first game is not going to be very good. That's just how life works. The first time you do something, you're not going to automatically be an expert. That's why I'd suggest starting small. Don't try to make another Home Together. You'll just get overwhelmed. Try something smaller. If you want to use Unreal, try making a game similar to something like House Chores. Except in Unreal with free movement. Limit yourself to one smaller area, only a few characters at most, and only a couple of scenes per character. If you make it through the smaller project, then make something bigger. But trying to make a large game while learning how to code, learning to use one of the hardest to use game engines out there, and learning how to animate, isn't a good idea. It's going to end in disaster.
I don't mean to be discouraging, I just want you to have a real idea about what you're getting into. It's really easy to want to jump into something like adult game dev, but it's a lot of work. It is effectively a job that you'll have to work at, and most of the time, you'll have to work for free. If that's not something you're prepared for, then that's totally okay. There's plenty of games out there you can enjoy.