Converting NetCDF dataset array to GeoTiff using rasterio Python

I would recommend looking into rioxarray for your dataset.

You can open your dataset like so:

import rioxarray
import xarray

xds = xarray.open_dataset('D:\Weather data\et_01012018.nc')

If your CRS is not discovered, you should be able to add it like so:

xds.rio.write_crs("epsg:4326", inplace=True)

Then, you should be able to create a geotiff from the Evapotranspiration like so:

xds["Evapotranspiration"].rio.to_raster('D:\Weather data\test.tif')

If this does not produce the correct results, I would be interested in learning more about your input file data.