I'm perhaps pathologically frugal myself. I've found for myself the best compromise is to force yourself to pick at least one feature other than cost. We've got a 17 year old Toyota Yaris that I tell myself is for fuel efficiency, and an old Ford Ranger because I wanted at least one of our vehicles to be able to move sheet goods. Technically I could probably walk onto most any lot and pay cash for whatever I wanted, but I know there's zero chance I'll ever do that.
With cars if you wanted to bias yourself towards newer cars you could prioritize safety features alongside cost.
A Yaris and a Ranger (who doesn’t love a Ranger!) are going to serve you well, but they’re not going to have the active and passive safety features of a more modern car. Put next to cost it makes it a bit harder to perform maladaptive frugality.