Republicans aren’t very strongly against those things (as they are abortion). So it’s not going to energize them to such an extent.
I'm sorry, Republicans aren't strongly against gay marriage?
https://static01.nyt.com/images/2018/10/23/opinion/23bruni-n...
The 2016 and 2020 platform both said that marriage is between 1 man and 1 women, they didn't mince words. Pretending Republicans won't try to overturn gay marriage is about as stupid as the people who said they would never overturn Roe v Wade.
Southern Baptists largely didn’t care about abortion before the 1970s, even seeing it as a good thing in some cases. From The Baptist Press, who of course now spouts the party line that abortion is terrible and this SCOTUS decision is wonderful: https://www.baptistpress.com/resource-library/news/southern-...