How to remove siteName from the og:title tag with SEOMatic
Yes, it's definitely possible to do that, but you'll need to use Twig as per: https://github.com/nystudio107/seomatic/wiki/10.-Dynamic-Twig-SEO-Meta

However, you might not want to do that. Sometimes it's nice to have the site name show up in the title that's shared via social media, to tie in the branding. Your call tho!