Hey Tony,
to answer your first question: I truly belive (and also really hope) that MODX will stay for a long time. Yes, the YouTube side is not as filled with tutorials as it is for other CMS’ but you will find atleast one thread in this forum here for any question you might have and if not, there’s loads of great people here to help you out.
Depending on your own background and coding skills, MODX tends to have a steeper learning curve but once you get the hang of it, you’ll learn to love the flexibility and freedom it gives you for almost any webproject (atleast that is the case for me).
If you want to dive deeper, there’s an older post regarding The Future of MODX.
For any Cloud related questions, I would probably just send a direct message via the contact form at modx.com.