Warranty swap the gas control valve as it has failed. Drain the heater, swap the GCV test for leaks. The hub drain is too close to the trap, increase the vertical length and adjust T&P discharge line accordingly HVAC will need to come out to re route one of the condensate lines with a pump. Expansion tank is still holding air, but is getting there in regards to age these units typically last 6 to 7 years and the one that’s in there currently was installed in 2021. Replace expansion tank and have it properly bracketed