I tend to do things the manual and long winded way, ticking the boxes as I go.
All of these thing werk, it's just that sometimes I like to be in control especially if I have not used something in anger.
The Windows file and docs transfer utility was a bit quirky to start with (seems OK now) and so I always had a copy of data on a different device.
As long as you have the old machine and it still is working, then there is no real risk, only wasted time and effort.
Helps to have patience - must be all the fishing I did (untangling knots etc).