It is certainly possible that by the time we leave that financial support (and private military contractors) would be enough to enable the government to withstand the Taliban.
But I don't think we should risk it. The very fact that we have to wonder if the government could hold should tell us all we need to know about a peace plan with the Taliban.
And the idea that we could carry out counter-terrorism operations if the Afghan government can't hold is plain wrong:
“The idea of scaling down to a small CT-only mission has long been discussed in the U.S. government,” [Laurel Miller, a top State Department official working on Afghanistan and Pakistan policy during the Obama and Trump administrations,] said. But, she said, “if you stop backing up Afghan forces in their main fight, you can’t very well keep working on your narrower priorities in isolation with Afghanistan falling apart around you.”
I recently brought that issue up:
Effective counter-terrorism requires the pinpoint information that a large network of non-special forces can provide--in the initial Afghanistan campaign to overthrow the Taliban regime it was local allies; in Afghanistan and Iraq when our allies ran the government you needed the friendly troops (American, coalition, and Iraqi) to provide the information needed for the counter-terror special forces missions to go after the enemy insurgents and terrorists.
Otherwise "counter-terrorism" is just a euphemism for using air power (planes and missiles) directed by aerial recon against targets in a sanctuary.
How do we target terrorists if we don't have allies controlling the ground where the terrorists live and plot?
