Heightmap importing poorly

I’m trying to import a heightmap I created in photoshop, but it’s giving me these rough edges and not smoothing anything out.

The problem may be that it keeps reading the .png as not a grayscale image. Every time I try to import it, it tells me that it’s a color png. I made sure in photoshop multiple times that the file is grayscale, I tried exporting with the embedded color profile, making it 8 bit instead of 16, I’ve tried everything. But it apparently it won’t read the png as greyscale. I’m not sure if it’s photoshop or what, but if anyone has insight on how to fix this would be nice.

Thank you!