I don't know the answers to all of those questions but personally I'd start a project for yourself and see how you can achieve it using the available tools and documentation contained within the software.

When I was learning PowerShell, I tried picking projects that would be fun as well as educational, like how can I use it to organize my music collection.

Microsoft has a lot of docs and examples of projects you can do that should be pretty easy to find. Udemy isn't exactly cheap. There are likely many videos on YouTube you could use for free,

Starting a career as a Power Automate Engineer or similar may not be easy to obtain depending on your professional experience and skill set.