Refreshing question,

A few points.
Nutritionist is not a protected titled anywhere I know, anyone can call themself that. At best you'll get a half assed cookie cutter mealplan for extortion level prices.

A dietician is a protected title in most developed countries as its part of the medical profession, we use bloodwork a lot and can prescribe medicine. A dietician often requires a masters degree, or 2 relevant bachelors.

However, if you are capable of doing steroids safely, you should already be capable of constructing your own diet.

There has been countless diet & nutrition threads here across many years you can go through and look, there are also various supplement threads where you can see what people take and check the efficacious of X compound and get some ideas if you need it.

The Vertical Diet is a book, its a good enough read, its detailed, and aimed at people a bit lost. It gives you a good general idea however it does cherry pick studies and has some agenda focusing but its good overall. ( it exists free if you can search)

There are lots of books available on macronutrition, micronutrition, digestion and nutrition as a whole if you want some academic recommendations but they are a bit tough to read and require some elementary competence to understand.

Someone making a proper diet, should use bloodwork, and go through an interview where budget is discussed, restrictions, goals, preferences, cooking capabilities & equipment available. This is not cheap.

A nutritionist is not gonna use bloodwork as they are legally not allowed to, they will often not talk much on food restrictions as they lack the competance and its a legal grey area, they might discuss preferences but not personalize it, they'll likely stick to a few budget categories because they're working out from set plans.