It sounds like what you want is a personal coach or the knowledge and experience to make your own plans.
TR has plans. Why not use them? After going thru a couple plans, you will not only understand how the plans are built, but also understand yourself better w/regards to structured training and recovery. Along the way, you will discover some workout that you love and of course some that you love to hate. Add said workouts to your favorites. If not doing a plan, you will have your own collection of workouts for your own purposes.
Using your Galen +4 example. It’s 4x20min @90-95% FTP. If you open up Galena +4 or search on Galena, you can see all of the variations which might be sufficient. Otherwise, you need to build up to 4x20. Maybe that is progression that goes 3x10, 3x12, 4x10, 3x15, 2x20, 5x10, etc… Bottom line, only you know you!