OP- great write up. Huge fan of the Cherohala, highly underrated. I get up there with the Civic X+ wake the dragon event in my Si. The surrounding roads are where the real magic is. Check out moonshiner 28 too!
Following.
Unbelievable that your dealer is that useless. Ask for their master tech and get out on a drive with him.
If you do have to go to another shop, take the bill to the dealer and claim under warranty.
Do you hear any hissing?
UPDATE - flash to KTuner Dual basemap (I am now on TSP but will post a separate update with more detail)
Vehicle: 2022 Civic Si
Total tuned time: tuned since about 33k miles (12/25/24) this update is up to 35,555 miles
Tuned miles driven: 2500ish, about 1500 on Dual 21
Tuning device(s) used...