Deactivated Yoast - lost image on Facebook link shares

Hi,
I have a problem, which may be outside the scope of this forum - It's related to switching to GP and not using Yoast anymore.

Basically I have been recommended to not use Yoast, because of it slowing the site down. I'm fine with not using Yoast.

However, we have 15 support articles, written for our customers, which they frequently share on Facebook. So it's very good organic marketing for us.

When I had Yoast installed on our previous theme, I could "control" what was being showed. And it even showed/pulled an image from each unique article.

Now, with no Yoast, it does not show the image anymore, and it seems to be pulling the H1 twice. Please see this example: https://www.dropbox.com/s/9sbc1cn8qp1y1c8/Yoast%20OLD%20vs%20Not%20Yoast%20NEW.png?dl=0

Do you have any recommendations on how to solve the double H1 problem, and the image as well?

The image example is from this specific page: https://www.blojfri.se/vill-inte-bajsa/

And I use the Facebook debugger to "scrape" the page again: https://developers.facebook.com/tools/debug/sharing/

Thank you :)