You can also do 'breakthrough' workouts on a dumb trainer. When you're riding to RPE and make more power because you're feeling good. You're not riding to a limit you may have fixed too low.
ie. we're all doing regular FTP testing aren't we... are you setting arbitrary load values for those tests?
I just use the ramp test in trainerroad, it does a good work on setting FTP for further workouts, can't say if it's any close to real world numbers. If for any reason it feels too easy just toggle the intensity a small % up (or down if my legs are cooked)
You can also do 'breakthrough' workouts on a dumb trainer. When you're riding to RPE and make more power because you're feeling good. You're not riding to a limit you may have fixed too low.
ie. we're all doing regular FTP testing aren't we... are you setting arbitrary load values for those tests?