... since this will prevent LFG from showing that the Commander's map is full.

Moving yourself (Commander) to a separate subgroup was once used to help others to find the player whose map they should join. But this is no longer needed, since

Commanders and lieutenants are now sorted first in their subsquads following the patch on November 8, 2022.

But since LFG apparently uses Subgroup1 to determine whether a Squad's map is full, keeping this habit does more harm than good.

Yep, I agree, LFG is a mess.