There is no succinct answer.
As a guiding principle, short focussed sessions that you return to frequently across a week are more beneficial than one extended session with many days passing before the next session.
Whether 2-3 minutes is sufficient is dependent on the technique.
A] Chord formation of a single challenging chord? 1 minute per session. A reasonable mastery can come in a week or several weeks.
B] Being able to improvise over a jazz standard incorporating the techniques of arpeggios and chord tone targeting and modal scales and more? A decent chunk of time with a long term view of months and years.
That is a chalk vs cheese comparison.
Read about both here.
Check discussions (use search) in the Community.
Bottom line.
Do you want a play-along guitar karaoke machine with hundreds of songs and many functions to help you play with other learning tools and all Grade 1-3 video lessons of the beginner course and more or do you want full chords / lyrics with a transpose tool and full giitar tab for every song lesson (700 plus) on JustinGuitar?
Isolate the section(s) that cause the challenges and give you difficulties.
If you are trying to play a song from start to finish and always fumble in one section then stop doing that.
You can use freeware called Audacity to import an mp3, reduce the tempo (not speed) and you can edit by trimming down to the section you need to work on.
Create multiple copies of that section at (say) 60% and 65% and 70% and 80% and 90% and 95% tempo.
They are your mini backing track tools to help you learn it correctly and incrementally gain speed until you can play it at full tempo.
When approaching full tempo, change the edit to expand it so it includes bars preceding and succeeding the tricky section. In that way you can learn and practice the transitions into and out of the tricky section at a reduced tempo and build that up incrementally too. In time the whole section can ge reinserted to the complete song.
Whereabouts in the course overall are you with your playing ability?
Justin has these courses.
He does introduce the idea of transcribing in small chunks at different parts of his courses. Have you reached those yet?.
I will direct you to the written and downloadable resources from Lieven’s Motivation club #3 and mine from Vintage club #4.
Your priorities and focus will come from an honest appraisal of your own playing and using mind maps and practice schedules can help.
Perhaps you could record yourself and, if willing to ask for constructive feedback from others here, share a video recording in the Audio-Video of You Playing section.
You are asking someone who lives the mental stimulation of learning theory and connecting it with the practical part of hands on guitar playing.
Knowing more stuff can be a shortcut, taken with a powerful engine and a large accelerator pedal, to playing more stuff.
Mmh … I’m not sure where the motoring metaphor came from! 
If you have healthy chunks of time and do not intend playing for 3 or 4 or 5 hours per day, you could apportion some time to ‘study’ and it not be at the expense of your playing progress.
Playing is priority number 1.
Theory is a good complement that often enhances the core business.
Is this picking individual notes / strings when practicing and playing scales? Ir arpeggiating chords? Or playing riffs?
There has been some useful advice and poi ters to lessons also.