For a long time all the complaints with TR were that the plans were too intense and they were burning people out. As such, TR came up with Adaptive Training and Red Light Green Light to help keep people from burning out. The default approach, especially with new users with limited power data, is a very very conservative approach from the AI.
As said above, keep doing your normal volume – adjust your available time in plan builder, manually change to longer workouts. As you compile more data in the TR ecosystem the AI will learn more about you and become less conservative.