i don't have much experience with Motion 5. My Final Cut projects maybe are not super complicated - i'm producing tutorials and some small forms, for IT companies and tech channels on the internet. For example internal tutorials about onboarding for new workers. But still much to learn about FCP.
I want to push my skill's for some other form's (maybe trailers or something new). Or pushing my current works to higher level. I'm using some 3rd parties plugins, transitions, stuff like that. But I want more control, understanding how things was created (transitions for example).
Sure - I've read some articles about Motion 5. But still I don't know, how much I can do with Motion. I want to create my own transitions, maybe animated intros, looped animations, some more or less complicated visual effects. Probably I'm talking about Adobe After Effects, but from Apple. Maybe something a little bit of motion design (but as far I know, there is nothing like that from Apple - better choice would be tools like Synfig Studio or Natron).
In few words - what I can do with Motion 5? Can I treat him like equivalent of After Effects?
It sounds like Motion will do everything you need and more - AE would be overkill, with a much steeper learning curve. Check out the stuff Mark Spencer, Simon Ubsdell, and Fox Mahoney have on the intertubes.