Dark matter is real enough from the observed effects. What it is made of is unknown. Attempts to detect it have so far found nothing at all. I have been lucky enough to visit one of the experiments in the deepest European mine. The near freefall lift descent is impressive particularly as the rush of air from the other car goes past.
Until a couple of decades ago you could have hidden dark matter as any old non-luminous ordinary matter - biros & chair legs were an in joke. But multispectral imaging has got too good. It has to be something that really doesn't interact electromagnetically much if at all.
I am less happy about dark energy but its influence is also observed. Clear evidence for that emerged after my involvement in the field.
Whilst as an astronomer I would obviously prefer big telescopes and planetary probes. I don't see all that much wrong with high energy physics as an area of research.
What they are doing in colliders closely mimics conditions in the early stages of the big bang. It may yet lead to important new physics - only time will tell. The unkind analogy is that it is like trying to understand clocks by smashing them together at ever greater speeds.
I found HEP and particle physics a bit too much like stamp collecting for my taste. There was an obligatory part 2 course on it. YMMV.
Blue sky research has a very long lead time before it shows what it can do. I remember seeing the world's first organic semiconductor a grey black slime with a very short useful life. Now Oleds are everywhere.
The gravitational wave detectors are also in the big science budget along with the next generation of space telescope. You never really know what you are going to find until they come on stream.