I have an accountant that manages the actual submission and a lot of the calculations but I log everything throughout the year.
What a professional is best for, in my experience, is advising on legal ways to minimise your tax bill, one being the deductions that you mentioned, but also other things the everyday person may not be aware of.
I would add that my accountant isn’t a specialist in trading or anything but I’m not sure they really need to be?
Dylan S