Humans didn't need any alien influence to discover triangles, all you need is a stick to draw in the dirt. Connect three dots and you've discovered the triangle.
The argument you're making is essentially the same as saying "oh hey, this unknown ruin is coloured red and the Feds use red so therefore it must be the Feds". Basic shapes like triangles are just about as obvious a motif to choose as a particular colour scheme is.
The other thing you're implying is that the ruin can't be alien because it doesn't match the style of the alien probes. That also doesn't follow. There could be multiple alien species. In fact I'm sure DBOBE mentioned that the remains of extinct alien civilizations was coming to the game, and I'd say that's what we've got here. See this reddit thread: https://www.reddit.com/r/EliteDange...turesruins_to_discover_in_the_galaxy/d7jfyhq/
Well, you have an alien monolith machine that has lots of blinking triangles running in patterns- very similar to the loading screen of our own UI. Two computers of some sort that run similar looking things.....
Let me clarify re aliens: the probes and wreckage are not human- and neither is this base. What I'm alluding to is that whoever built this base maybe had a hand with us at some point, either with technology or influence. Maybe they still do, as with Halseys little journey.
It just seems odd that you have an alien base use loads of triangles and triangle based geometry, and then have another race (humans) in the same game use even more triangulated textures, objects and art. Surely every race should be distinct? If its not, is there a reason?