What is the best fertiliser NPK?

[confusedchemist]

Hey guys
If I am entirely honest I am an absolute novice when it comes to orchid growing, but I have always found it incredibly relaxing and during my phd I seem to have collected a great deal more! I appreciate the sensitivity of orchids but have found a lot of conflicting advice on fertiliser choice. I recently bought some insect frass from a local company, Agrigrub, to use on my allotment but when I was looking at the NPK, 3:1:4, I noted it was similar to an orchid mist I bought from the garden centre. Do you think I could use this fertiliser instead? I don't want to kill my orchids so felt better to ask. Also this fertiliser has high chitin content but I couldn't find any advice online on whether that was good or bad.
Thank you so much you wonderful people
Nevi xx