I suggest the most advanced ride you can muster to afford and the tools that also accompany this ride. You like to tinker... so why not tinker with the newest road tech?

Ride each type of frame material and geometries, then pick the groupset that appeals to your tinkering mindset, and finally ride. Buying parts and stuff over time is almost natural for everybody, so you will undoubtedly have stuff to mess with too.

... Also, when I pedal, I try a smooth effort, never forceful. Nice on the knees but I would assume (based on everyone else's response) that mashing is harsh on the knees...