When I do a quick research all internet sources state there isn't simply any difference between using time adverb "just" with simple past tense and present perfect tense therefore saying "I just finished my homework" and "I have just finished my homework" or "I just ate" or "I have just eaten" mean the same. (Almost each source state simple past use with just is preferred in American English much more, some sources say "just" can be only used with present perfect tense)
I have a couple of questions with regard to function of "just".
If we use present perfect tense with time adverb "just" do we only imply the action happened in recent past or do we also imply there is a current relevance?
I believe there must be a reason to use perfect aspect of present tense with just.
I had asked similar contextual questions before on Ell Stack Exchange, allow me to wrap up my new question with context below.
In a context where I have been looking for my concert ticket for the last a couple of minutes is it correct to use below answers? (My friend informs me where the tickets are and I reply)
My friend: The ticket is on the desk. Me: I've just thought the same thing.
My friend: The ticket is on the desk. Me: I just thought the same thing.
I believe thinking is discrete event without strong current relevance and using present perfect with "just" is confusing.