I've been struggling for a few weeks trying to figure out why badges weren't showing on my S10+. Today I missed an important voice mail as a result and decided to switch back to Samsung One UI to see if ML was the problem... Deleted ML and within 30 seconds, the badges showed up. Switched back to Microsoft Launcher and they don't show... waited an hour and added a few new messages just to be sure. Nothing.... Is the problem with ML or with the app?
Solved my own problem. Restored the last backup and then went and touched something on each screen. I think changing the layout from 4x6 to 5x7 was what did it, but can't be certain. Seems to be working now.