No worries! Here is what to do:
In case of the tiles, in Wear OS 4 Google broke backwards compatibility, but the new Wear OS 4 compatible tiles are already in the app, but for now you will have to enable the beta test under “More Options” → “Behaviors” → “Wear OS 4 tiles”.
Watch Face Complications
The watch face complications are even easier. You will just need to re-add, or re-assign the watch face complications to the arcs. For this go to “Bubble Cloud settings” → “Favorite Cloud settings”, and tap each of the arc fields. Check the name of the complication that was assigned to the arc, tap on “Modify”, and select the same complication from the list (please see the video below where I show the process). Do this for all your complications and they will continue to work correctly on Wear OS 4, One UI 5.
Make sure to keep the Bubble Cloud watch face in the main list of favorite watch faces on your watch, because One UI 5 now resets the settings of watch faces that are removed from the favorites.
Thank you for sticking with Bubble Clouds, I do my best to make sure it stays compatible with new versions of Wear OS.