When I...a baby boomer...am..."fertilizer"?
There is a way to put things, and then there is a way to put things.
But putting that aside...
Yes...back in Sixteen, when the GOP fielded candidates like Rubio, I figured that the GOP would angle to get the Hispanic vote. On the american chessboard - the GOP could balance out the fact that the Dems "own" the Black vote, by owning the Hispanic vote. And one could envision them achieving that. Hispanics tend to have GOP values like entrepreneurship, and religiosity. One could imagine Hispanic Catholics allying with White Anglosaxon Evangelical Protestants to bolster the GOP. As Reagan said back in the day "most Hispanics are Republican. They just dont know it yet".
But in Sixteen both parties had surprise populist uprisings. Sanders almost overturned the Dem establishment, and Trump succeeded in overturning the GOP establishment. But Trump's winning populism was xenophobic, nativists, and outright racist. So my vision of a multihued Hispanic flavored GOP isnt gonna happen any time soon. Counter to my expectations they arent trying to cast a wider net to catch more voters. They opted to surpress voters.
Now that the GOP elite has made its deal with the devil by embracing Trumpism -its painted itself into the corner of nativism (if not outright racism). And (as you say) the demographic trends of generation and of ethnicity are running against them. So to stay in power the GOP has no choice but to rely on (a) voter suppression, and (b) stopping immigration.
What you say of Hispanics also describes blacks, namely they tend to be religious and social conservatives. They do not generally favor such things as gay rights, gender equality, etc.
Before Trump the GOP was coming to the realization that to stay relevant they would have to take a hard look at themselves. Then came Trump who believed they could squeeze out a few more victories by appeal to racist whites. It worked only once.