This is nice and all, but I don't know that it means a whole lot. There are few stakes for the people coming out to endorse Harris now. They don't work in govt roles, hold position in a political organization or an elected office.
The rank and file GOP (who are running for reelection now or in 2-4 years) are still sticking to the party line and the approved narrative. When they start flipping then it will be real news.
The article doesn't specify, but what kind of 'activity on adult websites' is damaging to the point that a candidate would be pressed to drop out?