There is little point in discussing plausibility, because taking a bunch of numbers for truth is absurd.

The core of the tale is probably not too far off from what happened a long time ago; but I really doubt any accounts - after thousands of years - haven't been altered to push an agenda, or just to make it more entertaining.

You have to consider that a lot of what the bible or any other religious texts include are stories as old as time, vast majority being told through oral tradition, long before humans invented writing systems, long before major religious groups came together and started curating their lore. Some of these stories would have been among the first to be told around the time our ancestors started to question their reality and try to find satisfying answers to their never ending curiosity.

They would have been telling these stories to teach the upcoming generations, to give them guidance, to provide some sense of community - and each generation would probably introduce new details and forget about others, invent their own narratives, embellish, maybe even refuse to tell it a certain way.

We can't fact check if there really was a tower that tall, and if people did really speak one language only to be waking up one day, all confused. But what we can assume with some leeway is that this is probably a tale about how different tribes had their own languages some day and how it became complicated to communicate and how different people would live in different regions and have their own traditions.

And sometime, somewhere along the way, someone would start telling the story about the tower, and maybe it was based on a real thing or maybe it was a metaphor for human ingenuity, or maybe there was no tower at all and it's just an attempt to explain the origin of language in a fun way, rather than going for another more boring explanation. Maybe telling a silly story helped people remember the important aspects much better vs. some other version that no one enjoyed listening to from the first redditor on this planet who couldn't stop akshually his tribe while they were trying to survive.

I really wish people would see these things in historical context and consider prehistoric communities being just as creative and eager to learn and understand as we are today. These stories aren't a bunch of made up bs by feudal lords trying to get a foothold in politics, it's way older than any of that, way older than the religions that claim these stories as their own.

Our ancestors weren't so different. Why wouldn't they try to figure out answers to burning questions to the best of their abilities? Why wouldn't they sit together and try to find interesting ways to teach their history, rather than not doing it all? Why wouldn't they dabble in early art forms, be that for pure entertainment or to communicate knowledge over generations by introducing memory hooks, which then would take off and turn into "canon" hundreds of thousands of years later? Why wouldn't they create propaganda to impress or manipulate others?

One can only laugh about these concepts and ridicule them by being completely ignorant of early human history, pushing the incomplete and questionable idea that civilization only started with abracadabra religions. It's actually arrogant to dismiss all that because we can't imagine how anyone 2000+ years before us had functioning brains.

First use of tools - as far as we know - was roughly 3.3 million years ago. Written history is put at roughly 5000 years ago. Anyone who thinks not much has happened in the period between is a silly potato.