I’d say learn multiple skills. It would be difficult for a multi-skilled person to not have a job. In fact I think such persons would have job offers at their foot and will choose which one they wish. Bitcoin and altcoins should not be looked at as a side hustle, because they aren’t hustle. Hustle is what actually brings the money. Bitcoin and altcoins may just increase the money you brought.
having multiple skills if not getting ventured further into developing the skills to the point where you become expert, you'd become jack of all trade master of none instead, usually the one that get pursued by jobs are the people that really excels at one thing, they are really good at it sort of expert in that field, that kind of person usually the ones that got the high paying jobs.
of course people can have different idea on how to better get a good paying job maybe through learning multiple skill but at least from my experience thats what I found, people with expertise tend to be among the one sought after by the big companies and instantly valued high because their expertise is needed and is the core solution to a problem company is facing so there's that one thing that I think worth to know.
moreover, i do agree though getting a job, may be should be the first priorities since usually crypto investing requires money to be there first.