2019 or 2021 Nissan versa worth it?

I doubt the 2021’s push-button ignition switch will be much of a problem. Looks like a pretty simple design, fairly easy to test & repair. If you want to worry, me, I’d be focusing more about the extra gadgetry the 2021 may have that the 2019 doesn’t. You might want to do some comparative research on their backup cameras, radar, sonar, adaptive cruise control, infotainment systems and the like. Then there’s the price factor. With manual transmission, both are very good cars. The mileage wouldn’t be of much concern to me as long as the pre-purchase inspection was ok. If the 2019 was $2-4 k less, I’d chose the 2019.