Hi AntonTd,
Nice work on all the structured training that you are planning for yourself. That is a good way to get better.
You have to think about your body as two machines. You have the fat burning engine and the carb-burning engine. That fat burning engine is the base. The carb-burning engine brings more speed and power to that base.
These engines always work together. So, you are always burning a mixture of carbs and fat. The harder you go, the more carbs you will burn. These engines are, for a big part, determined by your genes. Some of us are pure sprinters (like Cavendish), some are pure climbers (like Vingegard), and some are a little bit of both (like Pogacar).
With training, you can stimulate one or the other. If you are doing hard intervals all the time, you will lose your ability to do longer rides. And if you only do zone 2, you will lose your ability to ride fast.
That is why a mixture of training is essential, and I guess that is part of your problem, too.
While doing the sweet spot training, youāve missed a lot of zone 2 training. So you got good at doing sweet spot, but your aerobic threshold didnāt progress along with this type of training.
A lactate test would probably show it.
My advice is to ignore your zone 2 power and use the zone HR to do these trainings. Your power is not measured, it is estimated from your FTP.
You could also do the zone test on Trainer Day. It is a good test to measure your aerobic threshold. If needed, adjust your aerobic threshold and continue doing the great work you have done so far.
Have lots of fun, Coach Robert