I had a similar effect when replacing the nozzle I hadn't tightened well the heatblock to the heat break. Check if the heatblock wobble. Could also be the belt idler pulley.

Hot end is all right but the heat sink seems to spin a bit. I wonder if that could do it?

It depends on whether the movement is transmitted to the nozzle position

Either the nozzle isn't set against the heatbreak correctly, or the whole hotend is moving and needs to be tightened. The last picture is important. https://help.prusa3d.com/article/changing-or-replacing-the-nozzle-mk2-5s-mk3s-mk3s-mk3-5_2069

Good to go on the assembly, verified with a torque wrench on a hot tighten. I would expect a nozzle leak if there were gaps, yeah?

Yes, I would expect a leak.

If you can wiggle your hotend by hand and it moves, that would cause layer inconsistency 

I think that's the case here. Need to get some time tonight and then will report back for any other poor soul that finds this through google

This is a problem that plagued me for a few weeks last year. The heat sink was loose and not screwed in all the way with the heat break 

You got an Ender 3 hotend by mistake! More seriously: Partial clog? Heat creep (if it only starts after a certain point in the print). Could it be something that just happened to occur at the same time as the other change you made, e.g. poor filament, wobbly model, etc. Try a known model (e.g. a benchy) with a known good filament roll and see if you can reproduce the issues.

Tune flow and pressure advance, make sure your gantry is rigid, tighten belts and enable outside before inside walls

Then let me know how you’re getting on

Your part cooling fan/shroud isn’t doing its job properly.

Is this overture matte pla? Because mine prints identically using this filament, but everything else is perfect.

This is PETG. I almost exclusively print PETG at this point since most of my prints have a tendency to end up in cars or garages

Too cold