Lag is likely from the overly complex Figura model used in testing.

https://github.com/FiguraMC/Figura

Besides this bug, if animations are enabled, there will be a severe performance drop (0 FPS, can you believe it?).

Once the lag occurs, unless the game is restarted, the in-game rendering performance will remain severely degraded.

An additional suggestion: Allow switching player renderer modes via configuration files, such as 'Default', 'Figura Mod Rendering', etc.