I have the same problem with those annoying “Error: no handler found” messages.
They appear in Task Window of Visual Studio Code.
The output of the ESP32 board is shown correctly in the Terminal Windows.
So the error does not seem to affect anything, but is annoying.
The error shows up everytime i start a Build Task or a Upload Task in Visual Studio Code while Platformio IDE is loaded.
I tried a reinstall of VSC and Platformio, but the error persists.
On another machine with the same code the error does not show up.