I have not found my rear Spyre to be that great either, I score it as average. I am running V brakes on the front with Koolstop Salmon pads, they are almost too good. In rain, the Spyre beats the V brake, but that is the best I can say about it.

I have bought some resin brake pads and have been planning to try those instead of the stock TRP pads and rotor. But have not gotten around to it yet and since I leave town tomorrow for over two weeks, it is not going to happen right away.

Until I saw the first photo yesterday, I had assumed that you would be running drop bars and road brake levers. Are your brake levers of the long cable pull variety that are intended for use on mountain bike brakes? If so, maybe you have the wrong brakes. Road levers have a short cable pull, but pull pretty hard on the cable whereas mountain brake levers have greater cable pull but put less force on the cable.

This link says that Spyke is used with long pull brake levers.
https://www.trpcycling.com/product/spyke/

And the Spyre uses road levers.
https://www.trpcycling.com/product/spyre/