Alexander Smirnov has confessed that he lied about the Biden's receiving pay-offs from Burisma. Somehow, I doubt that Republicans are likely to back off on their claims even though the one who first made them has admitted that they were lies created with the help of Russian agents.
https://www.cnn.com/2024/12/12/politics/david-weiss-fbi-informant-alexander-smirnov-plea/index.html