So after following steps 1-9 of Raul1Argentina you then disconnect from the cable from iPad to computer. Then follow step 10. In step 10 does you iPad show up under the “connect to” (again not connected to the cable)? It should, when you choose your iPad there it should now connect through sidecar. It is now that the sidecar option will show in the status bar.
For some reason the icon does not show in the status menu, like it did in previous MacOs, until you connect it through step 10. I am not sure why this is, or if there will be a fix, but for now it just means a couple more steps to get to true wireless sidecar.