heavy cavalry engaging heavy cavalry

[Macedon]

Acrobolistae sounds an awful lot like Arcuballista, that's just an observation I'm not implying they were. Either way, what is the litteral translation of Acrobolistae?

Yes, the words are connected. The verb "ballo" in Greek means "throw, hurl, discharge", so a ballista or a basllistrida are machines that are used to discharge missiles.

Acro- here means "from a distance", regulalry akre means "top (of a mountain for example) or edge"

So, an acrobolistes is someone who stands on the side/edge at a distance and discharges his missiles whether in dispersed formation (skirmisher) or in line.

You can compare this with the word acrobates (acrobat), which means "walking on an edge, on a high point" or acropolis, "the highest place of a city, the city citadel" .

As far as I know, arcus in Latin is "bow" (the shape, like an English arc/arch) and so the direct Greek equivalent would be a toxoballistra (which is indeed a Greek word , as toxon means "bow/arc in Greek)