Nowhere in the 2020 "annual" of the Southern Baptist Convention—which includes its charter, constitution and bylaws—is the endorsement of a political candidate specifically prohibited.
By law, churches must be careful not to officially endorse political candidates if they wish to retain their tax-exempt status under Internal Revenue Service rules. But churches, including Southern Baptist congregations, have some leeway. They can publish and distribute voter guides, register voters or invite candidates to speak. Pastors and other church leadership can also endorse candidates as private citizens, but must keep their partisan comments out of official publications and not express them at official functions.