You can download all of the Rain X MSDS data sheets here:
https://www.rainx.com/safety-data-sheets/
Those sheets provide the ingredients for each of the different Rain X products. I glanced at the ones probably used for car/truck washes and I didn't see anything that would damage the TPO membrane. I would say, if you're planning to inspect/seal the roof, I'd do it before the carwash (I know, that defeats the purpose of the wash) so the DICOR sealant adheres to the TPO membrane. There may be (then maybe not) some issues with the silicones in the Rain X on the TPO. I suppose the silicone could interfere with DICOR adhesion if applied soon after the silicone is applied. After a week or so and/or a couple of rainstorms, the silicone would probably be washed away and not affect the DICOR adhesion (if it would even be a problem).
But, as for ingredients, you can also check the MSDS, but I didn't see anything that would damage the TPO.