That debug data could be good if you had a failure, but I don't think you do have a failure.
On the CLI, you can enter top
and then you will see a list of programs running.pay attention to it and see if you can identify something causing the concern. Press 'q' to quit.
Also, check the SWAP partition to see if it is being used. If it is above zero, it is being used, a few kbytes is not an issue, a lot is an issue, meaning you ran out of RAM.
If you have many applications running, stop them. Does the thrashing go away?
You can see where I'm going with this.
If you manually setup Scrub times, maybe you did that wrong and you are scrubbing all the time. You will need to do some investigative work because we need you to examine things and feed us the information you find out.
If you have nothing but a virgin system installation, that would be a problem given you have 16GB RAM. In fact, you may need to reinstall the TrueNAS application and then see what happens. If you are just starting things up then you should not have any data that isn't stored somewhere already. I'm also not suggesting you destroy your pool as I don't see how that would cause the issue you are having. But if you do destroy your pool, you can rebuild it. Again, I can't imagine this being a pool problem but if you wanted to start from scratch you might do this.
So lets see what you can come up with. It may take a little time but do not be in a hurry.
Good luck.