Have a look at daz studio. It's free as far as I know. Watch some YouTube tutorials for daz studio and download some assets from the development part here.
But you'll need a good graphics card for rendering.
Then have a look at ren'py tutorials. Ren'py is quite easy and chatgpt should give you...
It's okay for me, never did anything like that but I'm wondering how they've noticed these in the DMs. Seems like they were looking into DMs which would be a no-go for me. Maybe they just filtered through file size and noticed a huge amount of big files in DMs or so. But still a nogo
Give it a try. They are great quality renders and a great story as you may know from SSP.
If I remember correctly there are mainly pictures but a few "video" or animated scenes