If you have a research article, you do not post it on ResearchGate. ResearchGate is not a journal, it is a communication platform for professional researchers. You should publish it in a scientific peer-reviewed journal.
Yes, I agree with the first answer. Especially if you have faith in it being published in a refereed journal.
But not all papers can be published in esteemed journals. Many may still have value. There may be other ways of publishing those. If you're in the early part of your career, that's a good way of getting used to the publishing experience. Try to find someone putting together an edition of an e-journal, for example.
ReseachGate can be used to publish ongoing research. And pre-publication versions! So never think you cannot publish good works here.
When you're old like me, it might be nice to just publish here after decades fighting publishers. I now have no right to distribute some of my work as I wish to. Copyright holders dictate that!
Yes you should publish your MS somewhere and then post it is n RG subject to copyright rules. Sometimes due to various reasons a MS cannot be published but it has some importance to the research community or the society then you can upload in RG straight away as published data.