The pipeline is similar to yours:
gst-launch-1.0 uridecodebin uri=xxx ! \
queue leaky=2 max-size-buffers=1 ! \
nvvideoconvert nvbuf-memory-type=3 output-buffers=1 ! \
capsfilter caps="video/x-raw(memory:NVMM),format=RGBA" ! \
nvvideoconvert ! nvv4l2h265enc ! h265parse ! \
'video/x-h265,stream-format=byte-stream' ! filesink location=test.h265
And you can refer to the FAQ to get the higher resolution yourself. From the generated H265 file, it appears that there is no pixelated images in the video.
test.h265 (3.5 MB)