Douglas Coupland's mid 1990s novel Microserfs makes mention of a popular belief at the time that one should always wait until the 3.0 release of any Microsoft product before making serious use of it. Guess somethings don't change.

I haven't given net core 3 a trial yet but will use serial ports as my initial tests. In the 1.x and 2.x versions the serial port support was not up to the same level as the net framework.