If you have persistent fatigue, before you worry about yjj - how often do you work out, get your heart rate up, generate a good sweat? That will do more for your overall energy levels in a shorter timeframe than pulling yourself up by your bootstraps with an advanced qigong that you might not have the preponderance of time to dedicate fully. Blood plasma is the root of sweat facilitated by the spleen, so one good key to keeping the blood fresh and ultimately manifesting healthy skin and such is keep that circuit flowing. I cant stress enough how good for you it is to get your heart rate up and sweat every day, even if it is just for 15 minutes. You'll be able to turn that fatigue around in 3, 4 weeks easily so long as there arent other impediments, but for a normal healthy person that's a decent rough estimate if one is sincere. That's one other thing about yjj, a minor level of training is one thing but the full complete training and moving on to XSJ afterwards is really a vastly deeper level that requires time and commitment. Not that one cannot derive benefit from a less rigorous level of the training, but let's be realistic, there is more to getting your metabolism hoppin' than that.
(Plus if it is the rigorous training, it is bad if one stops the training before it is complete.)
If you have a drive to work, one thing you can do for guitar dexterity is to just run finger patterns on the steering wheel while you drive. 1-2-1-2-1-3-1-3-1-4-1-4-1-2-1-3-1-4 and what not. Play a lot of scales and keep the motion focused so that your fingers arent coming way far off the fretboard, chromatics are a good one in that regard plus are also a good legato exercise, even mix up picking and legato. You could always pull a Malmsteen and take a spare guitar, scallop the frets a bit on it, then if you're fretting too hard you'll sharpen the note. How crazy do you want to go?
Chunyi Lin at Spring Forest teaches small circulation just about right away - if you are interested in it, explore it. There are of course shallower and deeper methods. So long as you practice is not haphazard, keep good awareness, close into deep stillness after moving energy, you should be fine. Problems usually manifest because of breaking all sort of rules (and perhaps lying to oneself saying its ok, it wont matter) combined with building enough juice that it moves of its own accord and if not coherent...but really, learn correctly, practice with good awareness, learn to enter good stillness and these problems wont be on your path. It is a matter of opinion or school/lineage whether or not it is better for one to build first then circulate or to learn to circulate first then build...we're all a little different so different paths will resonate with some more than others.