Is it possible to plan missions/waypoints offline on your pc for Dji Go or in Dji Go like you can in Litchi ?
I looked at the waypoints in Dji Go but you have to actually fly it and record the waypoints ?
Then you can refly the waypoints automatically..
Is this correct ?

Yes, the reason why people pay for Litchi is so they can have access to those features to plan their missions before the flight.

Another downside to the DJI waypoint  setup is that you cannot name the recorded missions. Each recorded mission just gets a date time stamp and lists x no of wpts, thats all. Further you cannot even see or review any the stored missions preflight. The mode is only available for access once airborne.  So you waste precious flight time stuffing around through menus trying to work out which of your stored flights is the one you want based on a time date stamp.   I think the design intent is simply to allow you to  fly the planned route once, recording it, and immediately re-fly it again in WPT mode as an autopilot while you steer the camera.  I dont think it was ever intended to be a Litchi replacement quite possibly for good reason.