I can think of few ways to test your vSphere backup.
1. Deploy VCSA from backup, do not power on. Connect directly to the ESXi host (which runs existing VCSA) through Web client. Disconnect network from the main VCSA. Start VCSA from a restore, assign same IP address to it. You might see couple of warnings when it starts but they will disappear.
2. Yes you can assign different IP to your VCSA VM, but only in case you used a FQDN during installation. Your DNS server should have an entry for the VCSA VM. In this case, after deploying VCSA from backup and assigning a new IPA, just create new DNS entry pointing to this new IP. You might need to regenerate SSL certificates because of IPA change. This done through VCSA CLI.
Thank you so much for your inputs, i will try to test the VCSA with your steps and let you know if i have any issues.