I think your payment rate is a little bit low for quality articles, if you increase your payment rate it will help you to find good writers, especially as you look for long term plan, as you noticed.
exactly ! you HAVE TO INCREASE THE PAYOUT ! See the problem is you want a writer to write 1200-1500 words "UNIQUE writing not copy and pasted from anywhere, same for pictures" and you are roughly paying $1 for the original content i highly doubt you can find anyone to do this job. Even guys on fiverr ask $5 for a 500-800 word article (and most of them write shitty articles )