[naasking]

Yes, Vulcan was looked for just like DM has been looked for. The evidence for DM is largely indirect, just like the evidence for Vulcan. The OP's comment is a good summary of where we stand now. I suggest comparing all of the evidence for DM and MOND:

From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity, https://www.mdpi.com/2073-8994/14/7/1331/htm

There is definitely something to MOND. It would be a remarkable coincidence if MOND was able to make accurate predictions with only a single parameter, visible mass, what takes DM multiple parameters and a tuned mass distribution specific to each observable galaxy. DM definitely "explains more" in some sense because of how much more work it's received, but that's not saying much.