It is easy to get confused between the two and hence it is important to make a distinction. I personally remember the difference using a mnemonic - ETAL
In DevRel, Developer Evangelist is a person who acts like the face of the company. They evangelize the product as their role implies and it is mostly outbound
On the other hand,a Developer Advocate is someone who listens. They listen to the community and communicate back to the teams. It is more inbound than outbound
Although the distinction gets blurry sometimes, and it might be different for each company, this is more or less the baseline expectation.