In the IDE v. 1.8.19 running on MS Windows 10, serial monitor doesn't reconnect after Uno R4 board reset:
using Uno R3 and analog read example (analogRead + Serial.println), output continues after board reset.

Using R4 minima, it stops and serial monitor needs to be closed and opened again to get serial output.

On the other hand, IDE v.2 displays "Not connected" for a while and then continues to display output after board reset.