agree with these responses.
it’s also not as simple as “push 5% higher in every zone, FTP gets higher”, as some sort of blanket rule. You really have to approach each workout in the context of the overall plan or training week, and your goal for each workout is to get the training impulse that you are looking for.
Like, if you are going out to do a very long endurance ride and you bump 5% up off your target, you might end up fatiguing early and only getting in 3 hours instead of the 5 you were shooting for. That’s bad, will not result in better results.
If you are doing a super easy ride because you have an important and hard workout the next day, why would you risk not having as much to give during the hard day planned for tomorrow?
If you are doing a sweet spot workout and you push up 5%, you might be above threshold (on that day). If that makes you more tired and compromises the quality of your other workouts that week, that also could be bad.
On the other hand, if you’re doing Vo2max intervals and find that you are feeling really good and strong, and the purpose of the workout is to work on power (instead of capacity), and you push the intensity up, that can be very good (if working on capacity, you’d push the duration up, not the power up).
So it’s really a judgment call, you have to listen to your body but also think about it in context of the overall plan.