Also: "
to use a Spellcasting Focus, you must hold it unless its description says otherwise"
So if you are using a spellcasting focus to obviate the M component, you must be holding it.* Making that hand not free. (Noting in "this bit" you added the words "
or to hold a spellcasting focus" where they do not appear in the original text.) In 2014 the text
Somatic component text read (in part)
If a spell requires a somatic component, the caster must have free use of at least one hand to perform these gestures.
revised in 2024 to
A spellcaster must use at least one of their hands to perform these movements.
Reverting again to my argument that the Sage Advice text
added something: and that addition's presence in the SA text - the need for SA on the matter - makes its absence from the 2024 text telling (a reversion to the plain text meaning.)
*What the cleric and paladin spellcasting text is doing, is conferring the status of a spellcasting focus on a shield, so that in holding that shield you are holding a spellcasting focus.