Hi Tim,
At the ZWO site, they offer this for the ASI294MM:

- Screenshot from 2022-05-19 21-22-42.png (70.31 KiB) Viewed 1204 times
It would have been nice if they extended the graph to 1000nm like their ASI120 and ASI290, but my gut tells me that the QE doesn't suddenly drop to zero at wavelengths above 800nm. I think you are good.
BTW, here is my 290M. It's Altair not ZWO so I am making a major assumption:

- Screenshot from 2022-05-19 21-29-08.png (90.56 KiB) Viewed 1204 times
EDIT: I found this at the Altair site regarding my GPCAM2 290M:
Mono Camera: AR-coated optical window allowing UV or IR light through with 350-1050nm wavelength transmission.
(Note: An optional UV/IR blocking / Luminance filter with 400-700nm wavelength transmission in a C-thread housing to replace the existing one is available for this camera, product code: OW-GP-UVIR).
That's good news for me. It would be great if ZWO supplied as much information as Altair. By the way, does anyone know what "AR-coated" means? The only "AR" I know is "Augmented Reality". Seriously.
Next question: Will my (doublet) refractor focus IR? It's proven itself awful in Blue but does well in Green and Red. Hopefully that will extend to IR
Good luck,
Brian