In Hinduism, marriage is a Dharmik Sanskar. It has to be conducted as per Dharmik Vidhi Vidhan. LGBTQ marriage is out of question as goal of marriage is not a license for sex.

In Islam, marriage is a contract. Hence LGBTQ marriage be included in Muslim Personal Law.

Rest, if two men or two women want to believe they are married, why tamper Hindu Vivaah Maryada for that? They can just live the way they want and occasionally play "Taare hain baraati" song from Virasat film (copied by Anu Malik from EL Condor Pasa).

Hindu Marriage Act is to decide on issues of property, inheritance, children. Hence only those who can naturally reproduce are under its ambit. Else it will only create a child trafficking mafia in name of adoption.

Also, today same-sex marriage be given Dharmik certification. Then tomorrow incest. Where does it stop? If two men or women want to live together, no law stops them today.

Modify Special Marriage Act or create a new act if needed for LGBTQ. And allow them under Muslim Personal Law and Christian Marriage Act because one considers marriage as contract, other have members who encourage LGBTQ.
But Hindu Marriage have to be as per 16 Sanskars of Vedas.