This isn't a Red Flag Law. Texas has had that too for decades and it's spelled out in detail here. Before the legislature changed it about 8 years ago, there wasn't any kind of remedy.
A law enforcement officer who seizes a firearm from a person taken into custody under Section 573.001, Health and Safety Code, and not in connection with an offense involving the use of a weapon or an offense under Chapter 46, Penal Code,
shall immediately provide the person a written copy of the receipt for the firearm and a written notice of the procedure for the return of a firearm under this article.
(b) The law enforcement agency holding a firearm subject to disposition under this article shall, as soon as possible, but not later than the 15th day after the date the person is taken into custody under Section 573.001, Health and Safety Code, provide written notice of the procedure for the return of a firearm under this article to the last known address of the person's closest immediate family member as identified by the person or reasonably identifiable by the law enforcement agency, sent by certified mail, return receipt requested. The written notice must state the date by which a request for the return of the firearm must be submitted to the law enforcement agency as provided by Subsection (h).
(c) Not later than the 30th day after the date a firearm subject to disposition under this article is seized, the law enforcement agency holding the firearm shall contact the court in the county having jurisdiction to order commitment under Chapter 574, Health and Safety Code, and request the disposition of the case. Not later than the 30th day after the date of this request, the clerk of the court shall advise the requesting agency whether the person taken into custody was released under Section 573.023, Health and Safety Code, or was ordered to receive inpatient mental health services under Section 574.034 or 574.035, Health and Safety Code
(d) Not later than the 30th day after the date the clerk of the court informs a law enforcement agency holding a firearm subject to disposition under this article that the person taken into custody was released under Section 573.023, Health and Safety Code, the law enforcement agency shall:
(1) conduct a check of state and national criminal history record information to verify whether the person may lawfully possess a firearm under 18 U.S.C. Section 922(g); and
(2) provide written notice to the person by certified mail that the firearm may be returned to the person on verification under Subdivision (1) that the person may lawfully possess the firearm.
(e) Not later than the 30th day after the date the clerk of the court informs a law enforcement agency holding a firearm subject to disposition under this article that the person taken into custody was ordered to receive inpatient mental health services under Section 574.034 or 574.035, Health and Safety Code, the law enforcement agency shall provide written notice to the person by certified mail that the person:
(1) is prohibited from owning, possessing, or purchasing a firearm under 18 U.S.C. Section 922(g)(4);
(2) may petition the court that entered the commitment order for relief from the firearms disability under Section 574.088, Health and Safety Code; and
(3) may dispose of the firearm in the manner provided by Subsection (f).
(f) A person who receives notice under Subsection (e) may dispose of the person's firearm by:
(1) releasing the firearm to the person's designee, if:
(A) the law enforcement agency holding the firearm conducts a check of state and national criminal history record information and verifies that the designee may lawfully possess a firearm under 18 U.S.C. Section 922(g);
(B) the person provides to the law enforcement agency a copy of a notarized statement releasing the firearm to the designee; and
(C) the designee provides to the law enforcement agency an affidavit confirming that the designee:
(i) will not allow access to the firearm by the person who was taken into custody under Section 573.001, Health and Safety Code, at any time during which the person may not lawfully possess a firearm under 18 U.S.C. Section 922(g); and
(ii) acknowledges the responsibility of the designee and no other person to verify whether the person has reestablished the person's eligibility to lawfully possess a firearm under 18 U.S.C. Section 922(g); or
(2) releasing the firearm to the law enforcement agency holding the firearm, for disposition under Subsection (h).
(g) If a firearm subject to disposition under this article is wholly or partly owned by a person other than the person taken into custody under Section 573.001, Health and Safety Code, the law enforcement agency holding the firearm shall release the firearm to the person claiming a right to or interest in the firearm after:
(1) the person provides an affidavit confirming that the person:
(A) wholly or partly owns the firearm;
(B) will not allow access to the firearm by the person who was taken into custody under Section 573.001, Health and Safety Code, at any time during which that person may not lawfully possess a firearm under 18 U.S.C. Section 922(g); and
(C) acknowledges the responsibility of the person and no other person to verify whether the person who was taken into custody under Section 573.001, Health and Safety Code, has reestablished the person's eligibility to lawfully possess a firearm under 18 U.S.C. Section 922(g); and
(2) the law enforcement agency holding the firearm conducts a check of state and national criminal history record information and verifies that the person claiming a right to or interest in the firearm may lawfully possess a firearm under 18 U.S.C. Section 922(g).
(h) If a person to whom written notice is provided under Subsection (b) or another lawful owner of a firearm subject to disposition under this article does not submit a written request to the law enforcement agency for the return of the firearm before the 121st day after the date the law enforcement agency holding the firearm provides written notice under Subsection (b), the law enforcement agency may have the firearm sold by a person who is a licensed firearms dealer under 18 U.S.C. Section 923. The proceeds from the sale of a firearm under this subsection shall be given to the owner of the seized firearm, less the cost of administering this subsection. An unclaimed firearm that was seized from a person taken into custody under Section 573.001, Health and Safety Code, may not be destroyed or forfeited to the state.
https://codes.findlaw.com/tx/code-of-criminal-procedure/crim-ptx-crim-pro-art-18-191/