40 hours of 'work' a week at a firm does not equal 40 hours of logged hours toward certification.
At this point in your life, I'm going to assume you probably have a house, a family perhaps, a car or two, some financial responsibilities. You may be a bachelor with a bus pass, which would be the best case scenario. Working at a firm, or any place as a trainee, you should make a living wage, perhaps less, perhaps more. I know entry level people in the big city that make enough for a one bedroom apartment. Maybe you have a couple million in the bank from wise crypto investments and can totally focus on training, knocking it out in a few years.
Becoming a CG is twice as hard as a CR. Unless financially independent, not needing to worry about typical life expenses, bank on 5 years to get a CR while working, paying bills, taking classes, a weekend off or two, taking the wife out to dinner (if applicable), and for that elusive CG title, 10 years or less is impressive.