However those type of PCs function at 1st level. An eldritch knight is still a functioning Str/Int Fighter levels 1-2.yup all great examples... but even just the PHB has arcane trickster/eldritch knight/battlemaster/Bladesinger all things I can't imagine 'turning on' at level past 1
The STR monk doesn't work until it gets the subclass.
But the STR monk shouldn't be a subclass. The STR monk should be a fighting style..
Or at least the Monk should be able to choose between different Unarmored Defense options.