A new machine is the one moment when doing things in the right order is nearly free. Everything on this list is quick on an empty computer and tedious on a full one.
The order is the product
Recovery first: account access, recovery codes, a second factor that does not live on the device you are setting up. Then backup, before there is anything worth losing. Then data, then applications, then preferences — the layer people usually start with and the one that matters least.
The part everyone skips
Write down what you did. Which account the machine is signed in to, where the recovery codes are kept, what the disk encryption key is and where it is stored. The checklist has a block for this because the alternative is reconstructing it under pressure in two years.
Print it, tick it, keep it
It is a sheet of paper next to a new machine for an afternoon, and then it is a record of how that machine was set up. Both jobs are worth the page.