I could connect my IPP to my MBP(2018) with a wire but it was not listed in the display drop-down list when attempting to connect via WiFi. I was connected to the same WiFi, using the same apple id, Bluetooth turned on for both, rebooted both systems, logged out my apple id on both and back in, etc. I read through a ton of post and could not find anything that helped.
By mistake, i disconnected the cable while sidecar was running. There was a pop-up on the ipad that said something like - the display will start working when the connection improves. I went back up to the display drop-down while physically disconnected nd there it was. I clicked on my ipad and it connected via wifi. Disconnected / reconnected many times. Seems to be working now. Hope this helps someone.
By mistake, i disconnected the cable while sidecar was running. There was a pop-up on the ipad that said something like - the display will start working when the connection improves. I went back up to the display drop-down while physically disconnected nd there it was. I clicked on my ipad and it connected via wifi. Disconnected / reconnected many times. Seems to be working now. Hope this helps someone.