Welcome to the cafe! These photos were with a Z6. I have also used the lens quite a bit on a D500, which is a crop body. I believe I saw elsewhere that you’re also shooting a crop.I hope it is not too late to ask this question as I only joined the forum in the last few days. Can you tell me what camera you use and what lens you were concerned about, as I have had a Sigma c 150-600 f5 6.3 for about a week and I am finding it hard to hand hold at anything above 450mm and at 600mm it is really hard to keep it steady.
So would really appreciate any advice you can give me. My preferred image of yours is number 9 and if you were concerned about handling the lens from these images I have no idea why.
Hand holding a long lens is a challenge. Relying on lens or in-body stabilization helps, but is not a replacement for good technique, which takes time to learn. For my part, the non-VR 300mm f/2.8 was a monster to handhold, and by comparison, the 500 is lighter, longer, and stabilized: trifecta. One way or another, the lens has to be stable. Sometimes it still makes sense to use a tripod.
The only other tips I would offer for shooting telephoto is to favor higher shutter speeds when handholding and to nail the focus. You can correct noise resulting from high ISO in post, but blur and missed focus cannot be fixed.