I am using QGIS 3.18.
My .hgt SRTM files downloaded from the USGS website looks OK except when I try to apply hillshade to it. The parameters that I have used are summarized on the screenshot below. I have used cubic spline resampling to avoid the "blocky" rendering.
From far away, the result looks quite ok:
But when I zoom in, I have "contour-like" shading:
How do I make it look better?
.hgt SRTM files are in a geographic coordinate system (WGS84 EPSG:4326). Reproject them to an appropriate projected coordinate system that uses metres as the horizontal unit.
Alternatively, if you prefer to keep using hillshade symbology with your HGT files, you need to specify a Z factor reasonably close to the length of a metre (as that is the units of the Z dimension - elevation) in degrees.
At the equator, this is approx 0.000009, but see also this answer to calculate it for your latitude.
