Road bike recommendations

The problem with all this is you starting observing something and then made changes to your kit. The mere fact you started to care about your cadence would've changed your cadence. Changing to oval rings or drinking carrot juice or praying to a new god might all have magically altered your cadence or done nothing but you can't prove it either way because you introduced multiple changes to your riding at once.

How many gears two people might change is irrelevant. Everyone settles into their preferred cadence for a given effort. This can be trained higher or lower but it's individual and nothing can be gleaned from it other than you prefer different gears for a particular piece of road.

tl;dr

snake oil

Sounds fair.

Where can I buy this Snake oil?

Will it up my FTP?