I’ve been doing just that. I decided to try ramping up my TSS after reading about what some of the pros do. An example is Megan Guarnier. Case Study on Megan Guarnier: The Making of a World Tour Champion | TrainingPeaks Her peak power increased as TSS increased.
So I went from ~400TSS to over ~600TSS and it does work. Its hard to ride 2-3hours on a trainer, but I have the time and, since I don’t race, and just like to do a lot of outdoor climbing, I do these long trainer rides at lower cadences with my front wheel elevated to simulate the angle of around 6-8%. I also started to customized my own workouts with the TR Workout Creator.
Incidentally, I believe that big gear training is key to climbing faster.