You can use a VPS on 2 or more devices as long as you log into the VPS with separate credentials such as separate username and passwords and accounts.
To sign in to the VPS on 2 or more devices you need separate accounts to login to the VPS by creating multiple user accounts on the VPS server.
A VPS does not use your IP.
When you sign up for a VPS which is a virtual private server from a web hosting company the web hosting company will assign the VPS an IP address that is accessible by others on the internet.
Because the VPS is assigned it's owned dedicated IP address your internet traffic through the VPS will be identified by the VPS IP address and not your own IP address when accessing the internet through the VPS.
Every VPS server just like a dedicated server or cloud hosting comes with it's own unique IP address that is separate from your own personal IP address.
And although multiple VPSs reside on the same and single physical server, each virtual server or VPS has it's own distinct and unique IP address.
You use the VPSs IP address to access your server and manage your website or funnel traffic through and that helps with security as your own personal IP address is not exposed.
A VPS itself is just a server, and it won't hide your location by itself.
However some VPS do offer services to mask your activities.
And if you want to fully secure your connection and make your VPS untraceable, you can install a VPN on the VPS server.