No, we're not running out of fuel.
Peak oil never made sense as a problem, and still doesn't. I know that's an inconvenient truth for anyone who'd vested a lot of time and effort into the question of peak oil; but it doesn't help anyone to continue with a pretense that it's a problem.
That's because we can't afford to burn the fossil fuel reserves we do know about (whilst preserving human civilisation) let alone any undiscovered deposits. So it's always been the case that we were going to discontinue our oil dependence long before our oil reserves ran out, just as the stone age ended long before we ran out of stones (H/t Sheikh Yamani, Saudi Arabian Oil Minister 1962-1986).
The problem is that we have too much fossil fuels, not too little.
And there are already replacements for pretty much all fossil-fuel applications.
We know we can synthesise fluid hydrocarbons - the chemistry is pretty straightforward - which is one way to address the powering of heavy transport on road, sea and in the air. There may well be more economical solutions, but we know we have at least one working, scalable one. Some biofuels work, and are scalable too, so there may well be an increasing role for biogenic ethanol, and we've already seen viable biogenic jet fuel.
Fossil oil is also used for plastics; now, as long as those plastics are recycled, that's sustainable. However, for those plastics where we don't succeed in closing the loop, we'll have to find alternatives such as synthetic or biogenic materials. As far as I know, there are no impossible barriers thrown up by the chemistry there: the solutions are technically possible, but we haven't yet found the economically optimal ones.
And we already have highly-scalable fixes for the static applications of oil & gas: wind, PV and hydro all have well-developed global supply chains that have proven themselves capable of year-on-year expansion.
So although biogenic ethanol is one substitute, it's far from the only substitute. Hence, answering the ethanol question doesn't answer the question "are we running out of fuel?".
And although questions such as what share of global energy will sustainable biofuels have, what will be the best mix of fuels to power flight and shipping, and what amounts of shipping & aviation per year will be sustainable and economically efficient, are all presently unanswered questions, we do have an answer to your core question: are there viable sustainable substitutes for fossil oil in its current applications? And that answer is yes.