If you feed power from the 5V pin, U4_CP2102N will also be powered, and if you feed power from the ± pin, U4 will not be powered.
The output pins TX0 and RX0 of U4 are competing with the RX and TX pins you are trying to use.
If you feed power from the 5V pin, U4_CP2102N will also be powered, and if you feed power from the ± pin, U4 will not be powered.
The output pins TX0 and RX0 of U4 are competing with the RX and TX pins you are trying to use.