Junior, senior, etc don't only refer to someone's experience. They also refer to someone's responsibilities. A senior developer has more responsibilites. A person who has been developing for 10 years might not want more responsibility. A person who has been developing for 20 years might only be a junior at javascript but a senior at java. They could be very far along in their career. I don't really think early career is an appropriate label. An early career developer could also be a senior developer if they have progressed quickly or have prior relevant experience outside of their career.