Reddit mentions of SUNLITE Alloy Cantilever Brake

Just a heads-up, but check that the plastic collar between each brake arm and the fork (i.e. on the brake boss) isn't cracked. Most, not all, Exage cantilevers came with an underengineered plastic ring there. If that plastic ring is cracked, you'll never get the brakes adjusted right. For some reason, Shimano decided the return spring that gives your brake arms tension should be fitted through a hole drilled through the plastic collar. The tension invariably causes the ring to crack and split wide open. Cracks tend to be on the underside of the plastic ring, and can be straight enough to be mistaken for a design feature. You can often see the crack widening and narrowing as you squeeze the brake levers.

The fix is to buy new brakes. V-brakes won't work well because your levers are engineered around a different cable pull ratio than cantilever levers. The easiest replaement option, then, would be cantilevers without Shimano's plastic collar.

These worked perfectly fine on my mountain bike right up until the day I sold the entire bike:
https://www.amazon.com/SunLite-Sunlite-Alloy-Cantilever-Brake/dp/B016QRKKRI

I replaced mine with these generic canti brakes - comes with the arms, a yoke cable, and pads but no brake cable. It is a less of a headache to go with these than v-brakes, which require different brake levers (long vs short pull), and I didn't want to go down the rabbit hole of upgrading everything.

https://www.amazon.com/Sunlite-Alloy-Cantilever-Brake/dp/B016QRKKRI