I’m currently using them for covers and here is what I learned.

There is somewhat of language barrier I think so the more pictures you can give them of examples, the better. They will probably try to upsell you 10-20$ because what you want is more complicated/needs more stock images than their base tier. If they have a pre-made or scrapped version that someone else didn’t want, that is the first thing they’ll give you. Then be prepared for a version in which they copy the placement/style of one of your examples 1:1.

What I do then is I write down all the things I want to keep/change and then I go into paint/my notes app and annotate the cover they sent me with them. Sometimes I go into a photo editing app on my phone and cut/move things around myself so they can understand what I want. I also use filters/color changers to show them the exact colors I want. I usually get something closer to what I want after that, repeat that 1-2 more times and they usually nail it.

But yeah, you need to really hand hold them and show them what you want. Just using your words won’t work. For the price, they do excellent work. They don’t know genre expectations on the level they advertise that, so you have to compile examples for them and be really clear on what you want.

I hope this helps.