04 Chevy S10 shudder at idle but fine once above 1k RPM
 

Please see the video for a demonstration. I routinely get a 300 misfire code.

Have tried: New intake gaskets upper and lower, new fuel pressure regulator, new MAF, new OEM distributor cap and rotor, new O2 sensor on bank 1 (originally was getting lean codes on bank 1 but those are gone now), new vacuum lines (except one hard to reach one), fuel injector cleaner in the tank.

Have not tried: spark plugs, wires, ignition coil, other various sensors.

Side note: during the gasket job I noticed my dist rotor DOES NOT LINE UP WITH THE SMALL NUMBER 6 on the distributor when the balancer marks are lined up on the engine block. If I made the rotor point to the number 6, the marks on the balancer would be far off from the engine marks. No matter how many times I spun it around.

This feels like a timing problem TBH but IDK where to go from here.