The PiSugar2 is a battery board for the Raspberry Pi Zero. It has an integrated RTC chip available over I2C, but there are no drivers included in the kernel with the latest release of the pwnagotchi (or Kali in general). It's a ZXW Shenzhen SD3078; there is surprisingly little information out there about this chip. I suspect it's newish.
The PiSugar folks expect you to install Pisugar Power Manager, which is a web service to get battery status and set the RTC. I prefer to use the standard hwclock utility, because I don't need the extra function in the web interface. There is driver support for this chip in kernels 5.1 or newer, so we can grab that and compile it as an out of tree module. You may be able to adapt these ins