The RMT-based approach was chosen for sending and receiving. The timing is done in hardware now and therefore no more interference, i.e. interrupts of the application or the Wifi module is expected.
Transmitting:
The output signal is only very accurate, there is no more jitter in the carrier and low pulses.
Receiving:
Unlike the interrupt-based approach, no more codes are lost when there is WLAN traffic.
Note:
There is a delay with repeat codes that follow each other in quick succession because all the codes have to be recorded first. The “partial-receive-done” variant does not seem to work or is dependent on the ESP32 module