I want to hear you say that at one of the conferences/meetings of scientists I could witness live.

Some would tell you “yeah that’s obvious, we just need to look in these and those parameter spaces to find out!”

While others would tell you you are blinded by glory or whatever and cannot accept that we do not understand gravity because we think there’s mass there but really it’s just another correction term.

And some would spin off wildly into other directions…

So yes we have observed an effect and dark matter is a possible solution. But it’s not the consensus name for the effect as there are many camps which simply do not need matter (neither dark nor any other kind) as an explanation.