I'm having a lot of issues with them detached, both joy-con, sometimes alternating sometimes at the same time. I can't sit about 2 meters away from the main unit without them either being unresponsive, slow to react to inputs, or losing connection altogether. I've tried moving my phone and (powered off) laptop away without much success. When sitting within one meter of the unit the controllers don't lose connection and are merely unresponsive from time to time. I want to try moving the unit further from the TV but the HDMI cable isn't that long.
Same issues here. (where's the poll option for both of them not working?) Moving the switch base station around to different places seems to make a slight difference in how bad the response time is, but it still made shovel knight completely unplayable in TV mode. If I absentmindedly cross my leg in front of the controller, the ~200ms input lag will increase to multiple seconds of lag, and a joycon will occasionally just give up and turn itself off.