To work on a Deagle, you need a computer programmer, as they only exist in video games.
A DIY trigger job, even under Utube guidance is rarely a good idea.
One of the points of paying all that money to a good gunsmith is to both get quality work and have things "right" when you get the gun back. IF a smith screws up a part working on your gun, the cost of repair comes out of his pocket. (and if you run into a smith that doesn't work that way, do NOT give him any business!!)
If you screw it up ALL costs come out of your pocket.
Find a real pistolsmith, who will agree to do the work. This is not a job for Bubba the AR builder who has never done anything else.