Why are you pushing software engineers for "estimates"? You don't ask mathematicians how long that conjecture will take to prove. It's done when it's done.
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Tenured mathematicians are immune to deadlines, and non-tenured ones don't "story point" conjectures. Your PI does not usually make you submit daily status reports. Targeting a submission date three to six months ahead and trying again if it doesn't work out is a framework that would work in software engineering too.