I'd possibly use the ISOWeek() Aracade method to check the numerical ISO 8601 week (week starts on Monday) of your date field value, and compare it against Now(). And have this as a symbology expression. Something like:
//does not account for dates in the future
if ( ISOWeek($feature.yourDateField) == ISOWeek(Now()) ) {
return 'ThisWeek'
else {
return 'NotThisWeek'
}