Republicans better hope dems get more anti-catholic as the GOP continuing to increase its margins with white Catholics will be crucial to them winning elections in the future. White Catholics already went from 50-50 in 2000 to 60-40 by 2016 in the 2 party vote, by 2028, they will probably by 65-35.
That's going to happen anyway because basically all Catholics under 40 are hard right socons. However the percentage of Millennials who are Catholic has greatly decreased as well from previous generations, so it's not much of a blow.
Even if white Catholics shrink as a share of the electorate, if they shift decisively towards the GOP, the GOP will still gain in net terms, something like 15% of voters in 2016 were white Catholics and they voted 60-40 for the GOP which means they gave the GOP a net 3% margin overall, as 20% of 15% is 3%. If they shrink down to 10% of all voters which is where they'll be in a few decades time if they vote 70-30 for the GOP, they will give the GOP a 4% margin overall. Small groups voting overwhelmingly for 1 party are far more important than large groups who split their votes evenly. African Americans are a good example of that in my opinion.