21% is VERY dry and that level makes your guitar very susceptible to cracking. Do yourself a big favor and buy a good humidifier for your whole house.
I use Hercules stands - I use them mainly for my odd-shaped guitars like my Gibson Firebird and Flying V that don't sit comfortably on conventional stands but the stand would work just as well for acoustics plus it has a locking grip that holds the neck.
I was like you, fretting over the built-in tuner. Then I realized you can get a great soundhole tuner like this one: https://www.amazon.ca/dp/B018K9K034/ref=cm_sw_r_cp_apa_i_xdpgFbFRNTX5Q
It works perfectly, is tiny and discreet, and now you can truly focus on what's really important - the quality of the guitar itself which is what affects the tone, not some extra electronics that do not!
What did you end up doing?
Have it looked at by a luthier. I have a Gibson acoustic from the 1960's that has that, but it's also 50+ years old so I would be concerned if it was a guitar less than 10-15 years old. BUY A HUMIDIFIER! High end guitars like that need to be kept around 55% humidity, I believe. The wood will take in and release moisture, which over time can warp the wood unless you're humidifying it properly. This is the one I use:
You should buy a small humidity sensor to keep in the case with the guitar and/or in the room with the guitar. Don't trust your humidifier is putting out enough or too much. Govee makes some for $15 that connect to an app on your phone. It could take weeks for the guitar to respond to proper humidity.
For the room: https://www.amazon.com/Bluetooth-Temperature-Thermometer-Hygrometer-Calibration/dp/B07DWMJKP5/
For the case: https://www.amazon.com/Govee-Thermometer-Hygrometer-Bluetooth-Temperature/dp/B07R586J37