Need help diagnosing my 96

Jeep Cherokee 1996 4.0 4wd

I've had an ongoing issue with it that started early this year. It starts up fine, but sounds awful. Bad idle, engine shaking / vibrating abnormally, loss of power and acceleration, worse fuel efficiency, misfires. For a while that was it. It would still run and get to highway speeds. (Neglect of this for a time was bc I was broke, is what it is)

I changed the spark plugs a few months ago, and it went back to running smooth. For about a month. Then the issues came back, and got worse. It'll run as described above for about 10 minutes before the misfiring and power loss gets severe. The engine bogs down and sounds REAL bad, instead of just pretty bad. (Lol)

One day after about 10 mins driving it started doing this, and the power loss was so severe it would NOT go over 25 mph.

Okay. So I've checked all the spark plugs. They are sparking and connected correctly in order. Replaced fuel filter. Added fuel system panacea juice. Checked for fuel pressure in the injector fuel rail. Plenty. Replaced upstream O2 sensor. Replaced MAP sensor. Checked fuel injectors with a screwdriver stethoscope to verify consistent clicking.

What's next? Vacuum issue? Downstream O2? Panic?

Help!