the ac on my 98 corolla seemed to run fine until I turned the thermostat knob to hot and it stayed hot for a while. I turned the knob back and forth a couple times and got it to blow cool (not cold)after a while. I hear the compressor going, but still hot air.
My guess is the blend door. That means the little door that controls which (cool or hot) air is to blow into the cabin is not working. I worked on an older Corolla once and it was not too hard to get to and fix, but I don’t know about yours. It could be just a leaking vacuum hose.