Not sure what’s wrong but I use the solution of @ZenVoich which works great.
Solution was originally shared in this thread but it seems the current code has been migrated to TS so here’s the direct link: https://github.com/ZenVoich/mops/blob/e4e3b51df1c561b5b00a8e6eef25dcb85b531964/cli/pem.ts#L15