Resolution of the Syrian war requires wisdom, deep knowledge, empathy and incentives towards a pathway.
Super power backing of a peace table is also needed in this case due to the involvement of Turkiye, Iran, Russia and other external actors.
If not for Putin's retention of Assad a peaceful solution would have been found years ago. My view is that Syrians can negotiate a future for Syria if Assad stays away.
HTS is a problem but an attempt to negotiate must be made. Negotiation won't be successful with Assad still in the country. He needs to return to Moscow and stay there IMO.
The US can't enforce a cease fire but it could encourage a cease fire (on Assad's departure) and provide a safe table with chairs for discussion between the Syrians themselves.