I think the way I'd go about this is by using referencing user attributes in Liquid in a sql_always_where in the explore.
(note: Community doesn't like liquid tags, so please replace all of my parentheses with curly braces {})
If you have an email field, you could write something like this:
sql_always_where: (( _user_attributes['email'] )) = ${user.email} ;;
You can use Liquid to write in a few admin exceptions:
sql_always_where:
(% if user_attributes['email'] == '[email protected]' or user_attributes['email'] == '[email protected]' %) 1=1 (% else %) (( _user_attributes['email'] ))
= ${user.email} (% endif %);;