What's the deal with WEBM videos and what the BEST PRACTICES to deal with them?

I have lot of WEBM videos that I need to deal with in my workflows,

I noticed for the first time that using them WEBM videos (thansk to a plugin: https://www.fnordware.com/WebM/)

Causes my EXPORT process to FAIL (https://community.adobe.com/t5/premiere-pro-discussions/error-compiling-movie-accelerated-renderer-error-1609629695-using-wavs-and-webm-video-plugin/m-p/14229273)

I tried some website that convert webM to MP4 but they could not handle big files unless you.. paid.

I tried with ffmeg but the resulting mp4was.. corrupted? So I am turning into the community and the adobe staff/experts:

1) What are the best practices with WEBM videos, can we convert them and deal with them in some easy straighforward way?

2) I wonder why we can't use the media encorder tool to deal with it? That woudl make things easier.

3) Was that plugin safe? uninstalling it through (programs (in windows)) is enough?

Thanks