Bon sang, ça fait 31 ans pour moi et 29 ans pour toi.

The braid joints were animated via a rudimentary physics engine, rather than hand animated like rest of Lara.
The physics engine used spheres and boxes to represent solid objects like her backpack and neck to collide the braid against. Ergo, independent of polygon count.

It just needed tuning...

My experience was the classism was pernicious. Quite a few working class in the trenches but rarely in positions above that; "Congratulations, here's a job on the production line but don't get ideas above your station" It's been similar outside gaming, just with less exploitation and abuse.

My PC ISA devkit had the first GPU as did the blue debug stations, so we were used to the extra jankiness during development. The later green debug stations had the revised GPU as did Yarozes.
Retail consoles with the first GPU are rare, anything much after Western launch is revised version.

Technically the original GPU truncates the values from the gouraud shader DDA to 5 bits before modulating texel colours, whereas the revised version uses 8 bits resulting in visibly less quantisation noise.
Changes were also made to speed up transparency and frame buffer effects.

Lara's arm had a tiny 1x1 (!) texture map so it clearly illustrates the banding but so does her backpack and torso. It's also very apparent in Tomb Raider's first level entrance with the snow that has the wolves footprints. Many other games demonstrate it too.

My understanding is the extensive playfield compositing features of VDP2 were added later to augment VDP1 which renders sprites/quads to framebuffer. This was due to VDP1 having lower throughput than the (also in development) PS1 GPU.
Exactly when this happened in development process I dont know.