After updating to the beta version of Start 11 1.27 the issue is different, i no longer have the grey slider bars but at two rows high, i only have 1 row of system tray icons, and the far right icon (MS Teams) is kinda cut in half.

if i increase the task bar to 3 rows high, it is better in that i now have two rows of system tray icons, and none are chopped, but i have a third row of wasted space below

For now this is at least usable, but hopefully you can get it back to working correctly with two rows high task bar and two rows of system tray icons.
Rhys