Corey Smith has been a Sitecore since 2017. He's very active in the Sitecore community on Twitter @sitecorey. He's knowledgeable on Sitecore having years of experience. On his blog you can read about JSS, SXA, or any new topics. He's presented at multiple user groups including the Toronto user group. His presentation was around getting started with JSS. Overall, he's someone I recommend to follow in the community.