That is funny - Energizer NOT a Duracell.
The X2 manual states it should last 7 days on one charge when not integrated with the CGM and 5 days when running integrated. We don’t run ours into the ground to test this but the day to day usage appears to be inline with this (based on battery percent meter).
Typically we just plug the X2 in during showers as the pump is taken off for the shower anyway so no difference.
We can also charge it off a portable USB battery which we normally have for the phones anyway. Plus in the car we have the USB chargers so it can be plugged in there.
Really turns out to be a non-issue. As mentioned, I had thought it was going to be annoying but once we had the pump this was nothing.
BTW - For the Dexcom receiver - why not just plug it in at night? Then you never have to be concerned about it. Those can be charged off a USB portable battery as well.