Short answers, pulled from the story.
Russia does not recognize same-sex marriage. Since the 2020 constitutional referendum, the Russian Constitution explicitly bans same-sex marriage, and Article 1(3) of the Family Code has prohibited it since 1995.
On the 17th of January 2023, the Grand Chamber of the European Court of Human Rights ruled by fourteen votes to three that Russia had violated Article 8 of the European Convention on Human Rights by failing to provide any legal framework for same-sex partnerships. The ruling places a positive obligation on all Council of Europe member states to legalize same-sex partnerships. Russia was expelled from the Council of Europe on the 16th of March 2022 and is not expected to implement the judgment.
Same-sex marriage was banned in the Russian Constitution following the 2020 constitutional referendum. The amendments passed unanimously in the State Duma and added language to Article 72 defining marriage as a union of a male and a female.
Pavel Stotsko and Evgenii Voitsekhovskii married in Denmark on the 4th of January 2018 and returned to Russia, where their passports were briefly stamped to acknowledge their married status. The passport official who applied the stamp was dismissed, the Ministry of Internal Affairs declared both passports invalid, and a court case accused the couple of intentional damage to official documents. The couple fled Russia citing threats to their liberty and security.
Support for same-sex marriage in Russia fell from 18% in 1995 to 5% in 2013, the year the gay propaganda law took effect. A Pew Research Center survey from July 2015 found only 5% in favor and 90% opposed. A 2021 RPORC poll showed a partial recovery to 12% in favor, with 75% opposed.
Because the Russian Family Code only requires that spouses be of opposite legal sex, transgender people who had not completed a legal gender change remained registered as their birth sex. On the 7th of November 2014, Irina Shumilova and Alyona Fursova married in Saint Petersburg using this loophole, with Shumilova still legally recorded as male. President Vladimir Putin signed a law in July 2023 that bans changes to legal gender on official documents and annuls marriages where one spouse has completed a legal gender change.