How do I fix the default (from bedrock samples) player client entity?

[stable torrent]

I'm using the default player client entity from the bedrock samples repository (latest version, 1.21.130.3) so I can add one animation, but the default client entity doesn't work.

I'm getting an error saying the first_person_item_rotation_factor is missing, which I can fix by just adding the variable to pre_animation, but I don't know what the value should be to make the swing animation play right.

(I also got a bunch of problems before this, but I fixed those)

So my questions are

1. Am I doing something wrong or is there a better way to do this (since it's weird that the default client entity doesn't work)?
2. If I'm doing it right, what should first_person_item_rotation_factor be set to?

[prisma estuary]

o nah its cz thats an older version