I will point out 1 fact not said yet. Sora uses a lever to downshift. But uses a toggle lever on the inside of the hoods to upshift. It can only be accessed from the hoods. And is tiff and not easy to operate.

I would find a fremeset you like, Synapse Sectaur, Domain and go for Tiargra or better as you can afford. SRAM is all good. But for Shimano stay with Tiagra or better to get the dual lever shifting.

Mark Shuman