AC Compressor on 1999 Chevy Blazer

Hi
New member here. I have a 1999 chevy blazer and am trying to get the AC going. Just blows warm air. Someone said the compressor needs replacing/leaking but I thought I'd try to R-134a with leak seal. When I start the process the compressor is always cycling on and off. On the gauge it starts at 0/low in the white then within 5 seconds its in the red zone on the gauge > 60 psi. Then the compressor kicks in and gets it back in the white. Then compressor goes off and it goes immediately back into the red zone on the gauge > 60 psi. So I want to recharge it with leak seal but it keeps going into the red zone every cycle so not sure if it's ok to recharge it. Any ideas? My auto repair level is just basic. Hoping someone might have some ideas to explain to me what is going on. thanks!!