Are social media Apps WCAG Compliant?

I have a use case where I need to show 10 error messages in one modal for a particular functionality if there are any errors. The current proposal is

1. To show user which error message user has checked and not upfront using Bold font and different color for unchecked messages.
2. On the contrary for checked messages it is a normal body text.

Relying only on font weight and color is not a good take on accessibility considered. So how are social or any other platforms handling such a case? Kindly share the inputs and examples if you have come across.