tl;dr

Can't they just have an option to see only your own personal stats at the end of a fight ?
ex :
dealt = xxxxx ; xx% ; role average +-xx%
taken(avoidable) = xxxxx ; (unavoidable)= xxxxx ; role average +-xx% ; deaths x
heal = xxxxx ; shield = xxxxx ; effective = xxxxx ; xx% ; role average +-xx%

That way you have your own infos to see if you were good, and if you're with friends or people you're confortable with you can share ?

If people request theses infos, they are probably the kind that would be toxic anyway, so it doesn't change much.
If someone doen't want to see their stats, just have it disabled by default and with a button to see it anyway.

Have that window impossible to screenshot with the built if capture tool too, so if people share it, it's proof they use a third party tool and shall be banned XD