Warcraft 3 player GRUBBY has a yt video that talks about the complication of making control groups with the tab system when selecting different units. AoE4 - Lots of Helpful Tips & Tricks! Control Grouping, Hotkeys, & More! - YouTube
Relic should make it so the unit highlighted in the tab selection should be the only unit that gets added to the ctrl-group… instead of adding every unit.
That way you don’t have to shift right click each unit to deselect them