What is EasyLoader?
SD-UPdater for M5StickC is below.
matsumo / M5StickC-SD-Updater
I had also a closer look at the PCB and recognized a "missing" component near the RESET button:
The part is C44 100nF.
Removed on M5Stack Fire to prevent Nois.
Parts arrangement of M5Stack
The MAX40200 is a great idea.
The following information may be helpful.
Cannot write to M5StickC on macOS Catalina :
How to solve the problem that M5StickC can not be written with Arduino IDE of macOS Catalina :
There is a way to attach a diode to the Battery Module.
Blog：USB Cable and Reset prevention
Level converter is required for connection.
resistor to connect
Meter PZEM-004T with Arduino ESP32 ESP8266 Python & Raspberry Pi
Modification TTL UART from 5v to 3.3v
level converter to connect
Measuring home energy consumption with the PZEM004T and ESP8266
There is a similar question below.