I don't have a source at hand but some studies have shown that sleeping under 7/8 hours (i forget) a day reduces your cognitive abilities more than you think. You can sort of adjust to 5-6 hour sleep schedule and feel fine. Emphasis on "feel". What's been found is that peoples feeling of how well rested they are doesn't change if they sleep less but people who sleep less than recommended amount learn much slower and require more effort to get the same results as those who have slept well.

So yeah you will survive but at a cost.

It was talked about on Joe Rogans podcast with Matthew Walker but I have heard it elsewhere too.