In case you don't know it: PyHanko provides a full and up-to-date implementation for digital signatures in PDF, including time stamping.
Yes, it is in Python and much more powerful/comprehensive.
I personally really prefer Python too, but unfortunately it is too heavy for Cloudflare Workers and similar edge environments (due to the WebAssembly overhead etc). It is survivable, but consumes significantly more resources.
That is exactly why I created this tool - it stays small and lightweight, and definitely would not grow into full signing support.