Edited for clarity.
Deleting or modifying the AGS will be severely detrimental to colder weather warm up time and highway operation, especially with the mechanical fan. I suggest doing more research or actually confirming stock operation before performing this “mod”.
I was in -20 degree F weather last year hunting and didn't have any issues. Recently, was in sub-freezing temps during a snow storm and also had no problems either.
I hit remote start for the truck while I was in the camper, let it warm up for 10 minutes and by the time I got in, heater was warm and only took another few minutes to get hot.
If you don't have remote start, yeah it will suck for a few minutes though for sure!
Can't tell you how it would have behaved with the AGS still intact though since it has been so long since I deleted it.
Keep in mind that I fully removed all of the provisions for AGS and well as installed a 180* thermostat.