Okay, so obviously you have it in hand. I’ll leave you to it!
If you read the previous part of this post, you will know that a simple reinstall or repair won’t fix the problem.
If you read the previous part of this post, you will also know that all flatpak software using WebKitGTK is crashing, not just one software.
Well, as I noted above, you seem to have it in hand.
After updating the just-released “Gnome Application Platform version 46”, the problem no longer exists. So this should be a bug introduced in the previous version.
Glad you got it solved. All good things come to those who wait.