Posts wrongly displayed in admin section after switching to a different theme

I know this is not where you come for support with Avada, but I refuse to pay for a support license since I am switching theme and builder anyway. However I cannot easily do this. I am now using a different theme (Blocksy) and when I go on the admin dashboard and go to posts (like blog posts) they are all displayed in a bizzare way making my user experience quite the nightmare.

You can see how messed up it looks here.

Is this possible to solve without nuking the website and starting from scratch? I will happily avoid that if I can.

If I don’t receive an answer here I will post on other support threads as well.