Thanks much PJ for your elaboration. Makes things clear.
The below points definitely make sense in xiao ecosystem.
1.SOC(State of charge)
2.PMIC(Power Management IC)
I found the board you showed with button here Adafruit IoT Button with NeoPixel BFF Add-On for QT Py and Xiao : ID 5666 : Adafruit Industries, Unique & fun DIY electronics and kits
Good to know about it as well as a reference.
I will continue work on this further after all these inputs to see how it goes further.
Thanks for all the time and help always.