From the article:

Last summer … Fast-forward to spring 2025. In the intervening months, Typst has been upgraded twice (to v0.13) and Pandoc has upgraded at least 3 times (currently at v3.6.4), and my templates don’t work anymore.

This template is from March 2025, and we're now May 2026, with four more releases to Typst 0.14.2 (December 12, 2025), and with Pandoc 3.9.0.2 (2026-03-19).