It was the Hebrews under David and Solomon. They left proto-Hebraic writings, even as far away as in the midwest.
They didn’t. There’s the Los Lunas inscription:
https://www.asc.ohio-state.edu/mcculloch.2/arch/loslunas.html
OTOH, the lead crosses often discussed were studied decades ago by Barry Fell, who found them to be based on various Latin mottos of old European dynasties and whatnot, a modern forgery.
Over thousands of years, there were plenty of visitors and probably trade, by lots of people. Fell pointed out that the first testimony regarding Precolumbian contact was reported by Columbus, who recorded an old retired diver in the Caribbean, who when youn had found (what turned out to be) a Phoneician coin on the seabed, and turned it into a pendant which Columbus examined and drew. Columbus researched his trip by interviewing Icelanders. In the late 15th c, the abandonment of Greenland was only a couple centuries at most in the past.
The Romans were very accomplished at seagoing trade with extremely large vessels. They were present in the Canary Islands and the Azores (and were not the first visitors/residents) and apparently reached South America:
https://freerepublic.com/tag/bayofjars/index
And there’s the Cocaine Mummies:
https://freerepublic.com/tag/cocainemummies/index