When I want to create a new watch face and want to add complications to it then there are empty slots as seen on the image. If I choose any of the empty slots, the watch face does not appear on the watch.
Apple Watch
I was having the same issue but was able to fix it by fulling powering down my phone (first), then powering down my watch. Then, I restarted my phone fully (first) and then powered the watch back up. The complications then showed up without issue. Hope that helps.
Side note - One other thing I did in between restarting (in case it matters) was that I went into the app store on the watch to validate that I didn't have any updates for my apps.
I was having the same issue but was able to fix it by fulling powering down my phone (first), then powering down my watch. Then, I restarted my phone fully (first) and then powered the watch back up. The complications then showed up without issue. Hope that helps.
Side note - One other thing I did in between restarting (in case it matters) was that I went into the app store on the watch to validate that I didn't have any updates for my apps.
Complications not working after watchos 6
