I feel early career and jr are both fairly pedantic. If you want to make a distinction I personally think Developer I, Developer II, Developer III makes more sense, but that's me. I have been told also by quite a few people to never call myself junior anything or accept any of those positions and to me that does make some sense. A colleague of mine about the same skill level his first paid gig was entitled Senior Cloud Engineer, and I was being billed as DevOps Engineering Consultant. That being said I wouldn't want someone to look at me and say on you have less than this amount of experience in years and then try to call me junior instead of respecting the years of yard work I put in teaching myself while I starved as a freelancer or the two bootcamps that I put myself through during that time period. And on the flip side of what has been said I don't think I would really want to work with someone who insisted on calling a person something they weren't comfortable with so I think we can agree that the argument goes both ways depending on your background and life experiences.
Here is an article that explains some of the mindset behind this point of view which is ironically written by a VP of Tech at Pivotal where my first gig was helping build their PEZ Portal, so I can really appreciate what is talking about.
(builttoadapt.io/@jmckenty)