Plugin drastically slows down website (suddenly)

Hey guys,
I’ve been using the plugin for a couple of months now and love it. Just 3 days ago though, my website started having severe trouble and many 500 errors. Today I’ve disabled all plugins and one-by-one reactivated them and found that Display Posts Shortcode was causing the overload on the CPU. I’ve left it disabled for now but I would really like to get it back up and running. Do you have any insights on this, on what might have caused it? The only thing I did recently on the website was to update all plugins that needed updating – something I do each month. This may have coincided with the changes, but only loosely.
Thanks in advance for your help.
My website is navina.ca