delinea
Hi,
Plz make a test with the standard Joomla template on your sites first, just switch default template to Protostar, for example, and share the article to social networks and see how it goes. If it works fine, then the issue comes from our templates, and it must be fixed. Incase that issue still happens in default Joomla, you can consider to use a 3rd party Open Graph extension which supports easy way to share via social networks
For Pagespeed GG insight, there are many reasons that affect this score, when you check with insight, it also recommends some suggestions to resolve issue. Or you can use 3rd party extension like JCH Optimize
Regards