Studies which compare fit amateurs to elite athletes tend to find that their fat oxydation ramps down earlier and is less at any power output than it is for elite level riders (which to a great extent have chosen their parents more carefully; we don't have the genetics to get there). Our fit amateur who isn't ridicilously genetically blessed and doesn't train as much is going to derive more fuel from carbs.
The corrolary to that, as your aerobic fitness improves, your ability to utilize fat both in totality and at a higher % of your VO2max is going to shift anyway without any dietary intervention. The unanswered question is the value (or detriment) of dietary interventions; the one which gets tested the most, which is low carb for a short while leading up to a race then a big dose of carbs the day before a race to replenish glycogen reserves isn't looking very promising. Permanent low carb doesn't even get tested anymore, because what would be the point?
N=1, but from personal observation, after some three years of training and improved fitness which comes with it (even though my power didn't dramatically improve - depending on duration, my power is 5-12% up from 2019 power curves, sprint is virtually unchanged), I do find myself less reliant on eating. Last weekend I did a tempo ride - three and a half hours, 202W average, just on water - this I couldn't do in 2019 (it also happens they were waiting on me at a tavern with homemade fresh food, cake and wine which made stuffing my face with gels less appetizing
).
If you just train to get fitter, you'll be metabolizing more fat.