Hello Laura
When configuring vPC peers, you can only connect to two devices. Specifically, Cisco states:
You can have only two devices as vPC peers; each device can serve as a vPC peer to only one other vPC peer. The vPC peer devices can also have non-vPC links to other devices.
Note some invalid configurations below:
You can find out more info at this Cisco documentation:
So vPC provides redundancy in pairs, and does not even come close to the level of redundancy made available by the spine and leaf architecture.
I hope this has been helpful!
Laz