Please don't let my question cause so much hate on me but rather let's also be realistic at times.
The hate may come not because of the question per se, instead for the fact you didn't search. I am sure this was asked plenty of times already....
Though I haven't invested a reasonable sum in Bitcoin, I've at some point after watching how the market and price of Bitcoin fell from over $69k to less than $14k something similar to what altcoins do
There's a difference: bitcoin has a history of recoveries from low prices to new ATH; most altcoins never recover from the low price.
1. Will Bitcoin ever fall to zero someday?
Possibly; sooner or later everything turns to dust. But most probably Bitcoin won't go to zero in the next 20-80 years.
2. What happens if it ever falls to zero?
Most probably nothing special. Bitcoin becomes worthless either because there won't be humans left (or internet), either because humans have invented something better and lost interest in bitcoin. Probably at that point there will already be no mining. However, all the relevant things would have happened before bitcoin going to 0.
3. Will Bitcoin go back to previous levels?
Previous levels as 60k, or previous levels as 1k? About 1k the chances are slim (but see point 1); for new ATH the chances are very good (although it may not happen this year). But please don't make purchases based on my expectations, I can easily be wrong.