UTM to WGS 84 conversion issue - arcgis

Question

I am trying to use ESRI latest land use data and downloaded a tif image from
https://www.arcgis.com/apps/instant/media/index.html?appid=fc92d38533d440078f17678ebc20e8e2
for example, shown here
https://lulctimeseries.blob.core.windows.net/lulctimeseriespublic/lc2021/16R_20210101-20220101.tif
When I load the image to ArcGIS pro, the longitude between A and B (corners) is 6 degrees, which is expected. The tif image is in WGS84/UTM 16N projection. I want to be able to find longitude and latitude of each pixels on the tif file, so I converted it to WGS 84 coordinate. However, after I converted it (by GDAL and ArcGIS), the longitude span between A and B is larger than 6 degrees. It looks like the transformer treat each grid on the image as equal distance instead of equal longitude/latitude. Am I doing something wrong here?
def wgs_transformer(img):
"""Giving geoio image, return two transformers from image crs to wgs84 and wgs84 to image crs
They can be used to translate between pixels and lat/long
"""
assert isinstance(img, geoio.base.GeoImage), 'img is not geoio.base.GeoImage type object'
old_cs= osr.SpatialReference()
old_cs.ImportFromWkt(img.ds.GetProjectionRef())
# create the new coordinate system
new_cs = osr.SpatialReference()
new_cs.ImportFromEPSG(4326)
# create a transform object to convert between coordinate systems
transform_img_wgs = osr.CoordinateTransformation(old_cs,new_cs)
transform_wgs_img = osr.CoordinateTransformation(new_cs, old_cs)
return transform_img_wgs, transform_wgs_img
def pixels_to_latlong(img, px, py, transform, arr=None, return_band=False):
"""Giving pixels x, y cordinates, return latitude and longitude
Args:
img: geoio.base.GeoImage
px: float, x cordinate
py: float, y cordinate
transfrom: osgeo.osr.CoordinateTransformation
arr: np array, band info of the img
return_band: bool, if Ture, return band info for the pixel
Returns:
latitude, longitude
"""
assert isinstance(img, geoio.base.GeoImage), 'img is not geoio.base.GeoImage type object'
assert isinstance(transform, osgeo.osr.CoordinateTransformation), 'transform has to be osgeo.osr.CoordinateTransformation object'
band, width, height = img.shape
assert 0 <= px < width and 0 <= py < height, f'px {px}, py {py} are beyond the img shape ({width}, {height})'
if return_band:
assert isinstance(arr, np.ndarray), 'arr needs to be numpy.ndarray'
lat, long, _ = transform.TransformPoint(*img.raster_to_proj(px, py))
if return_band:
band_val = arr[py-1, px-1]
return lat, long, band_val
else:
return lat, long, 0