Thanks for reaching out about this. I’ll be happy to leave this post up for our community’s insights as well, though you’re correct that Zoom APIs do not provide a .pfx cert file out of the box.
I’m not aware of another method to consume the API using the PowerAutomate connectors. Have you had a chance to reach out to their support with this issue to see if they are able to offer an alternative route or a way to avoid the .pfx certificate?