Mine started out at 2 hours and then went to under a minute, but the "preparing" is awfully slow. Now the "verifying" is taking its sweet time.
The preparation stage is always the slowest, as it unpacks and stages the payload.
The verification stage is faster, but there is a trap -- once complete, it requires the user to enter the passcode to authorize and proceed with the final installation, but if the watch is attached to the charging puck (as advised), the entry pad screen only flashes briefly before reverting to the normal clock display while charging.
I've seen this now with all the 26 updates I've done, and today during the 26.2 update, I did see the warning about the passcode, but the entry screen either flashed and didn't persist, or never came up, as the watch sat on the puck.
So I wasted 20 minutes letting it sit there thinking it was still in the verification stage, when it was actually waiting for passcode entry.
Neither the watch screen (which showed the charging clock display) nor the Watch app on my phone indicated it needed user intervention. Tapped on the watch screen and then it finally displayed the entry pad.
As mature as the Watch is, the UX is regressing. I can't pinpoint where it started since I jumped straight from an S3 to a U2, but I suspect in this respect it's 26. I wasn't caught off guard by the S3, or the U2 with WOS10.