NVTOP - terminal top-like app, works well for AMD GPU stats.

Mission Control - flatpak, windows task manager style process monitoring, shows GPU stats, much like windows.

MangoHUD, in game overlay, showing live fps, CPU and GPU usage

This are the 3 I tend to use to monitor my system performance

(If you running a Wayland powered desktop, that may be a source of issues. I’ve had issues that I dont experience in good old X. But that was some time ago. My 6800XT performs as well as I expect it to under windows. Running NVIDIA on Linux is generally a real chore, AMD has been plug and play for me)

You better off enabling compression on a dataset.

Dedupe, even with the recent improvements, has huge overheads and will generally degrade in performance as the dataset increases in size, as it needs to keep track of the ‘routing’ table in RAM to redirect the request deduplicated blocks to the actual stored data. Apparently the latest openZFS release reduces the speeds loses over larger datasets, but it’s still subpar compared to compressed data

Video files are already heavily compressed, you’d be better off transcoding it to a more efficient media codec, like X265 or AV1, to save space on video files

Roboquest