TMC2209 UART issues on rp2040

I can’t help you, sorry.
Looking at your klippy.log. From line 45 till 1834 are macros listed. You might consider reducing the amount of macros. Do you know how those macros interact with each other?
You could do yourself a favor and start with the KISS principle (KISS principle - Wikipedia). For Klipper users Failed to Load Crowsnest Extension - #4 by Sineos

Good luck, hcet14