Dallas is 11 hours behind Islamabad
There is no standard 8-to-6 overlap. Someone joins early or late.
The 11-hour offset between Islamabad and Dallas means there's no point hunting for a 9-to-5 overlap — there isn't one. If you meet regularly, fix one off-hours slot and rotate it between Islamabad and Dallas so the burden doesn't fall on one team. Because Dallas and Islamabad don't both observe daylight saving, plan to re-check the overlap around March and November.