I actually just went through something similar with my dissertation... Diving straight into your question, can share bit about my experiences with dissertation services. Being research assistant, juggling work and my own dissertation was becoming quite the balancing act, so decided to seek help...
I actually just went through something similar with my dissertation... Saw your post about Dify and had to jump in. It's funny, I've actually used their services before when was working on my Master's thesis. Decided to give it go after friend swore by their quality and punctuality. She wasn't...
Down the rabbit hole of dissertation research, that's where found myself about year ago. Could almost hear my professor’s monotone voice murmuring “get more sources, more data.” relentlessly in my dreams. And can tell you something? It was nightmare. Tried hitting the library and the internet...