“… there are moments where I am pretty sure I’m doing the same thing as the instructor, yet not getting the same result. As a beginner in Blender, I’ve found minor differences/discrepancies can result in wildly different outcomes.”
I think that’s ‘normal’ and like you say, will happen less and less as your experience grows. There are so many things that are really basic and don’t get mentioned each time in a tutorial (luckily, because that would make them un-watchably long and slow-paced).
Ask, if this occurs to you, so we can try to explain that part…Start over a few times ( I remember sometimes re-doing the same thing 5 times, before it finally hit me, what I was doing differently than the instructor) to see if you can figure out yourself, what you ‘missed’….Don’t be afraid to re-watch the Blender Basics and/or the Fundamentals (these are so packed with information, that you certainly have missed of forgotten some things).
And to make things a bit more complicated, a lot, if not most modelers have the Addon: Mesh > F2 enabled and that changes (improves) some of the behavior of F.
For instance:

Instructors might not always mention that certain behavior is because of F2.