If you really have "pllenty" of Priority Club points (this exercise will determine just how "plenty" your stash is!), you can try using their "any hotel anywhere" options. It's a poor value comapred to using Priority Club points for IHG hotels, but then using Chase Sapphire for gift cards is an equally poor value. High value from hotel points can only be extracted when you use them iwthin that hotel program, because then the costs are "funny money" staying iwithin the program and also you're buying "excess capacity".

Going outside the hotel program's own hotels, though, the hotel program has to pay cash just like you do, so the whole devalues into the equivelant of a 1%ish cashback program. Similarly, Chase has pay cash for gift cards just like you do, so the whole thing devalues into the equivalent of a 1%ish cashback program.

So if the "indie" hotels that you want are hard to afford with cash, they're aslo likely to be hard to afford with third-party points.

I thnk, however, you need to redefine "luxury" and recalibrate hotel levels with a little research. You would have been fine with a Crowne Plaza or a Marriott had you found one there? Well, those are "business" hotels, not "luxury" hotels. And because of the exchange rate being what it is, if you look for "business" hotels in Agra, you may find some that are no more costly ($100ish a nigh) than midscale hotels in the suburbs in the US tend to me.

The only SPG property in Agra (the ITC) is a couple miles away from the Taj Mahal, on the other side of the fort. Will you have a car?

(Years ago there was apparently a different SPG property in Agra, a Sheraton, that had a good further view of the Taj Mahal, but it seems to no longer be an SPG Property.)