There is no solution to describe. The resilver operation just takes time to complete. I have no explanation about the expanding rewrite count. ZFS does not report any trouble with the drive. I have not investigated further now that the drives are operating in the pool. Maybe more later on this topic.
The problem with the pool expansion when larger drives are installed appears to be a problem with TrueNAS Scale: [Should a pool auto expand where it can?]
There is a Jira report referenced in this forum post about the trouble.
Using TrueNAS Core I’ve successfully expanded pools this way multiple times. This appears to be a continuing problem with Scale.
The real surprise was that with 4 x 10TB installed and while the pool did not expand, Scale permitted a replacement of all 10TB drives with 4TB drive. When multiple replacement drives are scheduled at once, the ZFS resilver operates sequentially over each drive. In my case it took nearly a week to complete the resilver.
In the end, I just created a new pool with 4x 10TB drives and used rsync to copy the data. The result is what I wanted but this solution needed four open drive bays and a couple of weeks of trial and error. I happened to have the open bays on this server, but upgrades could be troublesome on smaller systems.