How to fix bad extrusion that's likely caused by high pressure in the nozzle
I think you are pushing filament too fast.

Let's go back to the basics: my hotend (old Ubis, ceramic) and extruder can push PLA at 230°C at max 80 mm/s * 0.5 mm line width * 0.2 mm layer height = 8 mm3/s.

At this speed it doesn't extrude very well, there is too much back pressure (see also 
                
            ). That extrusion speed means (I have 3 mm filament) 1.13 mm/s of filament speed (8 mm3 / 1.52 / pi).

You have 0.3 mm nozzle and you print colder, both of which cause more resistance to the flow. If 8 mm3/s is my absolute max, yours should be about 8 * 9/16 (ratio of the nozzle surfaces) = 4.5 mm3/s (really the max).

Considering the different print temperature, I would start limit to 3.5 mm3/s, which is 0.55 mm/s extrusion speed.

If you print 0.15 mm layers with line width of 0.35 mm, your absolute max printing speed should be 3.5 mm3 / 0.15 /0.35 = 65 mm/s (which is better not to reach, 60 is fine).

Try doing the following tests: after cleaning the driving gear, extrude 50 mm filament at 0.3 mm/s and measure how much filament has been extruded. Then repeat 50 mm with 0.5 mm/s, and measure how much filament has been extruded. Try again at 0.75 mm/s. Obviously don't touch E steps and extrusion multiplier. I'm quite sure that at 0.75 mm/s you will notice a measurably shorter length of filament extruded. At 1 mm/s you will see grinding (but not as much as now).

If you want, try at regular intervals 0.2, 0.3 0.4, 0.5, 0.6, 0.7 mm/s and plot a graph of the actually extruded filament length. It will look like the one in the video (where he extruded a lot more and weighed the filament, which is time consuming and more expensive).

And then switch to 0.4 mm nozzle if it's too slow for your needs.

Additional information

You use 2.85 mm filament with a direct drive, no gears. Judging from your video the radius if the driving gear (teeth) is about 4 mm, meaning 4*2*pi=25.1 mm circumference. The circumference is controlled with 200 steps * 16 microsteps, as result each microstep controls 4*2*pi/200/16 mm filament length, which is 0.05 mm3 and what you extrude along a 0.95 mm length (at 0.15 mm layer height and 0.35 mm line width). Basically your extruder has no control for moves shorter than 0.95 mm, but in fact it's even 4x worse, since you never get a single microstep precision (4 microsteps of tolerance is more reasonable).

You should probably use a much bigger nozzle, or 1.75 mm filament, or a geared extruder, or prints will never be accurate and you will have problems all the time, which you cannot physically solve.