I agree with your assessment of the Russian position. I disagree with the withdrawal from Afghanistan.

I doubt it was a political will situation, nor a cost thing. It seems more likely that it was a useful base of operations for black ops and asymmetrical covert war and influence campaigns against China. US contractors were making a lot of profit. And 20 years in Afghanistan hadn't managed to get the US to anything resembling Vietnam levels of unrest.

To me, the withdrawal from Afghanistan was either mission accomplished in establishing and embedding asymmetrical capabilities in the guerilla networks and/or a need to remove a weak holding in advance of a war with China to avoid it being a distracting front and/or a need to pull back materiel for redeployment. I am not convinced it was money loss nor political will.