Unless there's a structural issue, it almost always makes more financial sense to keep saving and replacing parts on an old car, than buying a new car. I kept my old Tracer until the subframe cracked under the Engine. I was probably putting $500-$600 a year into extra repairs to keep it on the road, but that's still only a couple of car payments.
On the opposite end, I probably spent upwards of around $1,500 a year keeping my Oldsmobile on the road over the years (mainly around gasket failures, radiator leaks, dash failures, all those things that can affect a 20+ year old car.
Eventually, I got rid of the Oldsmobile when the Transmission was going to need replaced, and bought a Tesla. That's not because it "made financial sense". I just wanted to enjoy a (much) better car. I could have replaced the transmission in the car and probably driven it another couple of years before it too succumbed to rust, and while it would have cost quite a sum, it still would have been less than a Tesla!
So do what makes sense to you. At only 1500 miles a year, I wouldn't invest a lot in a car. If I were in your shoes, I'd probably get an old Nissan Leaf. They're relatively affordable, and they don't go far in their original variants, but it's super convenient in the new COVID era to just plug in my car and know that it's sitting there perfectly fine. Not worrying about how old the fluids are, or how old the gas is getting, or any of that stuff is really nice.