After years of fighting it, I think I am starting to move into the “If you’re going to use TR, just use the number TR uses” camp. The point of FTP in your training app is to set the training zones for your workouts. The TR workout system will make the workouts easier or harder around that “FTP’ number, and that’s all that matters in the end. Arguing about the definition of FTP is meaningless in this context.
Having said that, I do agree with Kevistraining and would start with something in the middle and see where TR puts you in 30 days after it learns more. If you feel like the workouts are too easy, you can always accelerate the AI learning curve by picking harder Alternates until things settle in.