Goodman 4 ton residential - suddenly not cooling

Our home has a 4 ton AC unit that was installed around 2006. It's still using R-22 refrigerant.

This morning, I went to turn on the system and it's blowing warm air.

I changed the return air filter (which was last changed 6 months ago) and that didn't help.

I have some AC gauges that I used to troubleshoot my car's AC some years ago, but appears AC is AC as far the gauges go so I connected them to the Goodman system.

With the system off, I am getting a PSI of 160 on the low side and about 185 on the high side. My ambient temp is about 92 degrees.

When I turn the system on and let it run for 15+ minutes, nothing changes.

Put my hand on the high pressure and low pressure pipes going into the condenser and they are both at ambient temp.

Usually, in the automotive world at least, when it's first turned on, I should see a significant drop on the low side and eventually the system will "settle" after a few minutes with the low side creeping up to it's "normal" spot.

Nothing budges on either side here.

Further checks - there are 2 x 40 amp bus fuses feeding the system. Both are good.

The condenser fan is starting and running fast, so I assume the startup capacitor is OK for the fan. After removing the service cover, it looks like this startup capacitor is also connected to the main condenser motor. Can the startup cap fail in such a way as the fan startup remains functional but the condenser startup doesn't work ? Or are these "all or nothing".

Any ideas on what could be causing this ?