Unfortunately, switching to Trailing Edge mode does not resolve the flickering issue.
The above procedure worked, and the dimmer now shows configured with Trailing Edge mode in HA. I definitely see a difference in that the dimming curve itself is smoother now (less choppy), but once the dimming level is reached, the flickering continues.
I tried both in regular- and full sine mode.
I also recorded a video, but the forum tells me that new users cannot upload videos.
Meanwhile, I found a forum entry from January 24 that describes my issue exactly:
Since my lights are built-in, I don’t have the option to switch bulbs like the OP of the other post.
From this post and the various red series posts I found, it seems this is a hardware issue that cannot be resolved through firmware or configuration.
I’m happy to try any other suggestions though.