New Ender 3 Neo: stops extruding filament halfway through

[clkwrkbrd]

Hi, everyone! I'm running into some challenges getting my Ender 3 v2 Neo up and running. I've never successfully completed a whole print. What's happening:It prints a great base layer, good adhesion. It prints about half successfully. Then, it suddenly stops pushing out filament. The extruder wheel is spinning, so it's trying. But, almost nothing is coming out. When I pulled out the filament, I noticed there is a narrow section about 3 inches from the end of the filament. It's as though that portion is melting or being stretched out before it gets to the tip of the nozzle.

Video: https://youtube.com/shorts/sj_KCvZ91eo?feature=share
Photo of filament: https://www.dunawaysmith.com/assets/3Dprinting/print-filament-dip.jpg
Photo of half print: https://www.dunawaysmith.com/assets/...print-base.jpg

What I've done so far:
-Leveled several times
-Adjusted the z-index several times
-Checked for clogs (none exist = when I manually feed, the filament comes out perfectly)
-Calibrated the e-steps
-Adjusted speed down from 100% to 90%
-Tried printing a known good model (the included rabbit model)
-Reformatted the SD card and rebuilt the gcode files

I'm at a loss. Any suggestions? Thanks in advance for your help!