Tested for Win10 and Gimp 3.0.4/3.0.8-1/3.2 RC2.
Please don't take my comment as criticism, but merely a suggestion.
Ungroup layers and group selected layers are not Photoshop-specific features.
The corresponding plugins have been available since at least GIMP 2.10 (including GIMP 3).
About Merging Selected Layers [Multi_Merge]:
Quote:
Merges selected layers into a single new layer, preserving the original (non-destructive style).
1. This doesn't work for me – it merges the selected layers but doesn't preserve the original layers (it deletes them). Once you fix this, the name of this function should probably be New Layer from Selected (by analogy with New Layer from Visible).
Two layers selected:

Result of the action:

2. Changing the location of the 3 filter triggers (or adding a second location) from Layer to Layers, i.e.:
procedure.add_menu_path('<Layers>/Layers Menu')

