Yes, the Vikings were there before Colombus. It's more that Colombus brought America to our collective consciousness. After Colombus this knowledge was shared on a large scale, during the Viking time this awareness did not come any further than the Viking community.
Did you ever read Saint Brandan's journey? It's an old medieaval text about an Irish saint who set out to sail the Atlantic. And he did find land out there.
There are signs hat even in medieaval Europe there was a vague notion that there might be land beyond the Atlantic. Interesting subject!
Vikings were in North America long before Columbus:
https://www.sciencenews.org/article/vikings-north-america-date-newfoundland