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.

Didn’t work for me, though.

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

MBP M1

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.

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.