Everything you have done contributes to more felt vibrations.
Metzelers are a stiffer tire. If you're running them close to the Metz recommended, higher air pressure, that as well, is going to transmit more felt vibes.
Same thing with the higher spring rate Progressives and thicker oil. Stiffer suspension transmits more road irregularities to the bars and seat.
It might be possible to mitigate some of this discomfort by experimenting with different grips/handle bar end weights, and gel or other seat inserts. Perhaps padded gloves....but it is a natural effect of stiff suspenders.
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Hey look, a covered bridge...
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