They'll be zero overtaking if DRS is ditched
I'm not so sure that's true. A lot of overtakes happen under DRS now because it's the simplest way. Drivers just wait for the straight and go through, no need to try anything audacious or brave in to a corner - in fact at some tracks you're actively punished for doing that, ie. Jeddah 2021, where the DRS detection on the last corner means that you couldn't overtake there as you'll instantly lose the place again. It also means less wheel to wheel action because there's absolutely no point defending against someone going 15kph quicker than you down a straight. If you have pace to fight, then it makes sense to let them pass you, then try and hold on in DRS range to either try and re-pass again, or to get dragged along slightly quicker than you would be going in clear air.
There is no benefit to fighting.
However if DRS wasn't there would there be less overall overtakes? Most likely, but in reality most races these days have stats like '60+ overtakes' - but how many of those were memorable? How many got you on the edge of your seat? How many can you remember even a day later?
If we got rid of DRS would we instead see drivers defending more aggressively? Would we see more overtakes in unusual places? Would we see more bravery and skill? Would it improve the show? I'd suggest it's a 'yes' to all. A case in point being the 2 Alpines going side by side for the fist 3-4 corners of the Miami race, because they couldn't just open their wings and drive past the other. They have to battle it out properly for track position.