@Markus_Illenseer the ESP32 connected to WiFi will transmit the string received via the serial connection to a known address. The ESP-now message string is parsed by the ultimate end point, communication is one way outbound and always to the same address.
It’s very complete and encompasses much more than just serial bridging - you can control UARTs, change buffer, boot remotely, send and receive MQTT messages (controlling functions, for example), run in AP host mode, or connect to existing APs, all through the web portal.
An ESP32 can be connected as a client to a wifi network and be able to receive ESP now packets at the same time. I have a project that we use at our hacker space to send ESP now data from a battery powered ESP8266 to an ESP32 connected to the hackerspace wifi. The ESP32 needs to be connected on the same wifi channel as the ESP Now, it seems. Project link: https://revspace.nl/EspNowSkip