That said, earlier today I downloaded Karl Muck's recordings of Parsifal from the late 20's (there is some issue as to whether they are studio or live or a mix).
Muck has a direct connection to Wagner; whether we can say this is how Wagner would have presented Parsifal is not clear. But certainly Wagner's conducting informed that of Muck.
The recordings are a revelation. Incredibly slow to modern ears (the only slower tempo I recall is one of Toscanini) and yet not ponderous the music flows and takes the listener quite out of the ordinary realm. What is also remarkable is the quality of the recordings made just a couple of years after electric recording began.
Now, Parsifal is a controversial piece. Certainly Wagner perceived it as peculiarly Christian - but of course that does not mean he saw it as necessarily Aryan. Certainly Wagner's own writings do not suggest this. Now, that said, Wagner was no friend of Judaism.
The first performance of Parsifal was conducted by Hermann Levi, a Jew and the court conductor for King Ludwig. Wagner objected to a Jew conducting and King Ludwig replied Levi would conduct saying "human beings are basically all brothers". Wagner then (or so one reads online) asked Levi to convert to Christianity. Levi declined. Nevertheless, the conversion concept is incompatible with Aryan racism - the Aryan racist view would consider a former Jew who was Pope to be as much a Jew as always.
None of this, of course, has any impact on the music. Indeed, if one ignores the swastikas, some of the best recordings of Wagner remain the wartime works of Furtwangler.