

I haven’t purchased files to print at all, so I can’t answer about Etsy or Cults3D. However, I can speak to other aspects and hopefully drive up engagement to get someone who can help more in here.
1: Dunno
2: You’re probably fine to print most things. Probably nothing like nudity or sex toys (don’t print sex toys in general, but that’s a different topic), and then a lot will shy away from guns. Cosplay guns might be tolerated.
3: This is a complex question. You need to know your print volume. All prints can scale, but if it’s wearable you probably aren’t going to be wanting to scale. Most creators, including that in your link, will piece out larger prints to accommodate this. I would reach out to the creator telling them your print bed size and intended use, and they might be able to adjust the sizes/pieces for you.
4: filament is usually $20-30/kg. I can get a LOT of prints out of 1kg. And usually the creator or slicer will tell you the estimated grams.
5: Can’t speak to this one. I think I recall some negative opinions towards Cults3D back in the reddit days, but I forget why.
I recall seeing a lot of posts on here praising the leadership whenever they said anything negative about Trump
But that’s about the only stuff positive about Iran I’ve seen on here.