The party platform is the official stance of the Republican party and it is against same sex marriage. It won't change until 2024. Republicans who support it are extreme outliers, not the other way around.
https://abcnews.go.com/Politics/rnc-moves-2016-platform-inta...
> I’m pretty sure mainstream republicans are pretty onboard with accepting homosexuality
Less than half of Republicans support same sex marriage.
https://news.gallup.com/poll/311672/support-sex-marriage-mat...
If I was in a same sex marriage I would feel very, very uncomfortable working at a company that "bans politics" when a large number of my peers thinks my spouse is "unnatural".