The above picture shows the total circuit including FTDI (FT231XS), SH1106 OLED display, and LiPo charging circuit. OLED is connected through I2C with address 0x3c. DTA and RTS are connected to "Expressif data sheet" circuit. In this circuit, LiPo is indispensable for its operation and even not portable use, LiPo battery connection is recommended.....

The actual operation can be found in the following movie... Have fun!