I remember reading a book, Centennial,” written by James Michener.
In the forward, estimates were given about population of the Americas.
The time, from the first human to step on the North American Continent until the humans reached the southern tip of South America, was 14,500 years.
The average movement, Southward, was 8 miles per generation!
The only reasons to move was war with enemies and loss of food and water.
No mention was made about population numbers.
Also, the “land bridge that connected Asia to North America was much wider than I thought. I thought 60 miles or so. Actually it is estimated to be 600 miles.
Humans moved from Asia to NA and Animals moved to Asia.
The idea that there was one window of time available for the single Precolumbian peopling of the Americas persists, but is outmoded. Its defenders are dug in, but are getting older and older and will die off.
The Clovis-first-and-only model is, alas, getting superseded by the “anti-colonization” idealogy, which is inherently and irreparably antiscientific.
Humans didn’t move eight miles per generation, they were all the way down to Tierra del Fuego at basically the same time that the oldest cultural remains in Alaska. The strait wasn’t an impediment to migration (in the right time of the year, of course) and any folklore-driven culture would know the ancestors had crossed over from Asia, or had waved goodbye to the relatives as they migrated to the Americas.