I think it's Moses that tells Josh to 'choose men'... maybe Moses isn't a very good military guy... so yes, if the israelites are getting bad advice, then even a large force could be squandered fighting some small wilderness groups... then the stories would make sense, yes...
But God saw the number of troops as relevant because He punished Israel for not sending their whole army. He saw it as arrogance on their part.
Moses, Israel, ALWAYS won when YAHWEH said they would. the battle is YAHWEH'S.
When MOSES did what YAHWEH said, and if Israel didn't disobey, they won.
military cunning , numbers of men or horses, didn't matter.(and doesn't matter today,btw)
Israel won with 300 men against many thousands when they did as YAHWEH said to do(through MOSES and / or JOSHUA).
Sometimes, they won(like against 185K) without lifting a finger to fight. the battle is YAHWEH'S.
and if they disobeyed, they lost. or were punished. ("disciplined" may be more accurate sometimes).