There are so many computers on these cars and all draw down minute amounts of power. I lived in the valley of the damned all my life before moving north. My cars always went onto a DELTRAN Battery Tender Plus regardless of season or anticipated next drive. Batteries last a lot longer when they're always fully charged. Once they start to discharge, expect a shortened life. I've had OPTIMA batteries last ten years using a Battery Tender Plus.
I found this site
https://www.themechanicdoctor.com/ho...ry-sit-unused/ which might give you some reference. The DELTRAN site used to have an FAQ section but it's not active.
https://www.batterytender.com/
If you don't want to use a device, you can simply disconnect the negative side of the battery.