Not a problem Rafaela! Thank you for acknowledging. Although they are often used to say the same thing, does not mean that they have the exact same meaning. To comprehend subtle differences is to climb the ladder towards advanced proficiency. Good luck with your learning goals.

Hi Rafaela! "Meeting up" means getting together. If it's two or three or more people. We are all meeting up next Saturday." "Meeting on" alludes more to the day or date. "Are we meeting on Saturday?" For the birthday celebration we are meeting on the 25th.

They’re basically the same thing. There’s no difference in the meaning.