7-10 hours a week of training is a good amount for a 70.3. Since you’re a strong cyclist, I’d reduce that to less than 1/3 of your time and focus on the run and swim.
Triathlon training is a game of trade offs. You won’t have enough time or budget to do everything perfectly, so you have to focus on what is going to give you the best bang for your buck.
Getting a book will help you understand all the concepts and help you set up your own plan. If thats not your cup of tea, you should be able to find a triathlon coach that you can pay to do all the thinking for you.