I did a bunch of rendering for a mod as practice on my current rig and even rendering at 720p resolution it was taking me from 20 mins to 2 hours for most of my renders. So I've resigned myself to just brainstorming, writing story, dialog, code, basically doing the back end stuff for my games and no rendering at all. I have a few different games I'm working on right now but I'm stuck with a GTX 1050Ti (4GB). It'll save you a lot of time and the life of your PC. Ride out the scalping and save up for a decent GPU (A 10 series should be better than what you have, a 1660 served me decently when I was learning, too). In short: Anything other than just straight up rendering is always going to look like a step down, and even then it's not always going to be perfect. It'll probably still be noisy as fuck, but it's another option. Then crop out any UI elements and tryrunning it through a denoiser. Though, I suppose an external denoiser could help with that, or not. It's sorta cheating, I guess, and the quality'll probably suck comparatively along with having no room for animations (though with your system, that's probably not a priority.), but it's quicker than rendering at the same time.

I suppose you could also load your render in an Iray preview and screenshot what's in the viewport. Not as realistic, and borders on horrible if done wrong, but it's workable and likely a lost less of resource hog than Daz or something of the like is. I'd think your only other option would to be go the HoneySelect/Koikatsu route. Perhaps shoot him a message if that look is appealing for you. But he mentions that it's speeding up his renders on a laptop, so it might be useful for you. You could also try something more cartoon-y like what MrSilverLust is doing with his game Nothing is Forever, though I'm not sure exactly what type of shader he's using to get that effect. I suppose one thing you could do is render at a lower resolution, such as 1080p with the Daz Denoiser. I'd think the same rule applies to rendering (at least in Daz.) the more realistic it is, the more details need to be rendered, and therefore the longer the render. The higher the quality of anything, the bigger the file size. Goes for almost anything in a digital sense.

Daz3d photorealistic