sync problem stuck on step 2 out of 5 software up to date

It’s a bug in the current iOS or Mac OS version (no one is sure which). There are a couple workarounds that work for most people:

Plan A on the iPhone:

• Turn ON Airplane mode
• Turn OFF Bluetooth
• Try to sync again (this worked for me)

Plan B on your Mac: 

• Launch Activity Monitor (in the Applications/Utilities folder)
• start the sync
• In the Activity Monitor App, search for MDCrashReportTool
• Click on it
• Click on the “X” at the top of the Activity Monitor screen and Force-quit it. (This also worked for me)

Some people have also reported success with disconnecting their Watch

And I had success simply by unplugging my iPhone from my Mac and plugging it back in. In fact, I did that to both iPhone's and it did the trick, which was simple and painless.

Well isn't that interesting? All I had to do to get the sync to complete last week, was unplug the phones, and plug them back in and voila, the sync completed.

Didn’t work for me, though.

What computer are you syncing with? I have a MBP M1.

MBP M1

First thing I tried. I now have a solution that I can’t discuss, but there has been a lot of talk about this issue in the Appleseed forum.

Never been there, so will just wait till a solution is released.