A7iv unexpectedly noisy? Looking for advice.

Just got my new A7iv and the test shots are noisier than I expected. This image is a ~1000x1000 pixel "excerpt" from a full-res (33 MP) uncompressed RAW test shot.

Image taken from ~30' away with a tripod-mounted 200mm telephoto. Exposure is f/4 at 1/250 sec at ISO 3200.

It is a lot noisier than I expected. Is there an issue, or are my expectations too high?