Five of the 6 GCC countries permit churches to organize and gather for worship, Saudi Arabia being the one exception. It is helpful to review the US Department of State “Report on International Religious Freedom.”
Many congregations are actively meeting needs in their local communities such as providing assistance to low-income expatriate workers, visiting prisoners and teaching English to low-income locals. Search for churches in the GCC countries by entering “churches (country name)”. Some links will provide lists of churches while others will familiarize you with the particulars of specific congregations.