Could the limited naval ceasefire between Russia and Ukraine usher in further progress on peace negotiations?

Agreement on this doesn't really mean much. What matters is territorial divisions. I see this ceasefire deal as Russia trying to play the United States.

The deal would be reasonable if the U.S. would be willing to enforce it with sanctions if Russia reneges, which it will. Ukraine should not believe this deal is in any way credible if the U.S. is not willing to commit to sanctions if Russia reneges. So, the question is, "Will the U.S. reimpose sanctions if the Russia reneges?"

The deal also favors Russia if other parts of the agreement, like the repatriation of Ukrainian children, are not effected, and the chance that Russia would effectively help with the repatriation of Ukrainian abducted children is zero.

It appears that Russia has not compromised on any dimension.