No concerns here.
I buy used server chassis and power supplies for my NASes.
The only new items in my primary, backup, and offsite NASes are the 500TB of HDD’s and a couple of fan splitters.
The only new items in my 3 Proxmox nodes are…nothing actually. All SSD’s, HDD’s and everything else is used enterprise hardware.
Sellers can send offers to potential buyers. It happens to me all of the time.