Meh-ish. The goal is always on a gradient. It's entirely reasonable to look for the best way to "approach mastering a skill" on a deadline, because there is at least one deadline, and in reality there's always more.
No doubt, but somewhere between here and you dieing, I would assume that you semi-continuously revisit the progress per time and effort you put in and what you are getting out of it (maybe not so explicitly), and reconsider if "mastery" of that topic and as by your rules, is still a reasonable and worthwhile goal?
Either you never change your mind on what you master, or there is a implicit process by which it is changed, and I would be very surprised to learn that time/effort/progress do not play a role in that calculation.
Not really. I'm not fussed about leaving things unfinished when I die.
A few years ago I was deeply struck by an image of the late Grant Imahara's workbench [1]. It was cluttered with tools, notes, and unfinished business.
That's what I expect my desk to look like when I die, too.
