Lighter weight wheels and tires are the #1 upgrade to improve ride quality and potentially your accelerations. A high TPI tire should make the sidewalls more compliant and theoretically marginally smoother.
A 'new bike day' is often the best way to improve motivation. I do it very regularly, but in a value oriented way.
I don't race, so a 21# bike with tubulars rides mighty nice and fast enough for this oldster.
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Vintage, modern, e-road. It is a big cycling universe.