Just on the topic concerning Provincial Nomination, these programs were created to boost the economy and population of other provinces that are not as mainstream as Ontario, or British Columbia (due to opportunities).
If you apply to such provinces, there is a moral obligation to stay. Can you move despite this? Of course you can. But if you are not giving the province a chance and just move to Ontario the second you get your PR visa, you're gonna look like opportunistic and you only took advantage of the program. It will adversely affect the chance of other applicants in the future since there's a good chance provinces will tighten their requirements.
It's a give and take deal. If after a certain period, let's say a year or two, and you still could not find the right job / opportunity after so many tries, you can speak with the provincial immigration team and explain your side. At least it's an amicable exit.