Oh god... the story of what and how Robotech came to be is SUPER intresting, it involves the actual Italian mafia as well. The problem is for Robotech to exist 3 other series including Macross are not allowed to in the west, this has recently started to finally shift, but for all intent and purposes their completely diffrent series.
And to answer your question Macross Plus is an OVA series & a movie. The movie version due to the improved pacing and that few additional scenes is the superior version... ironically though it is missing the entire gif above, which is a shame but it gains so much more.
There's also the utterly beloved movie version of the original series "Do you remember love" which is canonicaly an in universe movie that retells the original animated series events for the people of the macross universe to watch. A bit like how we watch Saving Private Ryan that retells Omaha beach, the people of the Macross universe watch "Do you remember love" for their fix and it is phenomenal especially for 1984.
To put it in perspective studio Gibili's first movie castles in the sky would not release until 2 years later in 1986 and the Macross franchise was looking like that 2 years earlier.
Sorry about the off topic guys, but I get so few opportunities to gush about Mecha and normally its trying to get people into the gateway drug of Gundam and not some of the other super intresting stuff like Macross and Patlabor, which I will end this post on a GIF of because Patlabor 2 is sick and I love it.