“Under prior holdings of this court and others, an unexplained delay of four months or more can constitute laches and result in denial of mandamus relief. Here, relator’s April 6, 2021 petition for mandamus was filed seven months and six days after the trial court’s August 31, 2020 order denying the [Rule 91a] motion to dismiss. We conclude that relator’s unexplained delay bars his right to mandamus relief.” In re Tekin & Assocs., No. 05-21-00219-CV (Feb. 9, 2022) (mem. op.).