... - the US kind of hamstrung them in that they still had one leg in trying to do their own thing and one leg at the beck and call of the US and US interests - if the last few months had been a proper handover to full autonomy they might have had some kind of chance even if a slim one rather than pretty much no chance at all.
One of the reasons they collapsed so quickly was that many of their regular forces were strung out in isolated outposts, etc. ...
You're ignoring many times in the past where a high % of those troops (not all) abandoned their posts to let the US fight on their own. Only reappearing after the battle. The US being there had little effect on them either.