Two things, first the kind of rickety contraptions people used to cross the Atlantic in modern times suggest that crossing the Atlantic is not actually that hard, if you are prepared to tolerate some risk. Second the Romans had pretty good ocean going vessels, certainly better than a Kajak. So it should be possible, though the Romans did view the Atlantic in general as kind of a backwater and where more oriented to the East.

As far as I understand, when you have a ocean going vessel then there is not too much difference between different voyages, and the Romans did regularly sail from Spain to Britain and the Mauretanian King Iuba II did report on a expedition to the Canary islands, so they clearly had ships that could sail on the Atlantic. And by the second century the Romans did also trade directly with India, starting from the Red Sea and crossing the Indian Ocean. So the Romans had ocean going vessels.

Schulz's, Abenteurer der Ferne (2016), actually discusses the question for Phoenician sailors and concludes that the voyage could be made from the Canary Islands to Brazil, though the return voyage would be much harder due to the prevailing winds. So given modern knowledge, it seems possible but it is not clear what would motivate Romans to take such a risk.