Hoping to make sure I'm looking in the right places to diagnose this issue, any suggestions appreciated.

Issue:
At warm idle the motor almost feels like it is stumbling. From the engine bay it sounds ok (no loud noises or vibrations), but the vibration in the cabin feels really rough. Even with the harder engine mounts, it's an uneven vibration in the cabin, so I think something is off. Unless 264s idle that hard? Above idle (not revving it over 3k at the moment and no boost) moving at low RPMs 1.5-2.5k it feels smooth.

Risk:
This is my first cam install and timing belt job, and while I took my time and triple checked everything it's very possible something was done incorrectly.

New parts added:
Timing belt/balance belt and all related components, used HKS 264 I/E cams (degreed), new ID1000 injectors (sat in box for 4 years?), used ECMLink with SD (reset calibration and followed setup steps), new fluidampr harmonic balancer, flywheel and clutch replaced, added front and rear torque solutions engine mounts (trans/timing are stock), rebuilt turbo

Based on what I have read here and elsewhere, I was going to check the following in order:

1. Visually confirm cam gears are still aligned (skipped tooth possible)
2. Triple confirm ignition timing at warm idle
3. Turn off injectors one at a time to see if one cylinder has spark or injector issues
4. Confirm balance shaft position with screwdriver method
5. Confirm all timing marks still aligned (pull timing covers) and balance shaft marks aligned
6. Check compression and inspect spark plugs
7. Check intercooler piping for foreign objects (unlikely, but could've forgotten a rag)
8. Remove some of the advance from the exhaust cam ( already confirmed clearance wouldn't be an issue with returning cam to 0°) since it was further from 0° than the intake

I'm trying to check the easy stuff first, but if there are any other things I should check, open to suggestions. Can also post a log if needed, but I'm sort of assuming this is mechanical.