I was suffering from the same issue bro but then I came to know that the meanings of all these words are the same but slightly different from each other. I am explaining these words in one line as of my knowledge.
1 The currency that occurs only in digital form
2 It is a border term that includes all the terms.
3 The currency that uses cryptography
4 and is designed to be used as an alternative to physical cash.
In terms of bitcoin if you talk about bitcoin in general then I think digital cryptocurrency is good and if you talk about the specific feature of bitcoin then Electronic cash or cryptocurrency is best.
But my opinion is that if you use any terms it does affect the bitcoin so it's upon you to what term you use more.