Vcenter can be completely decommission without impact on VM. (only in case of share storage DRS, HA etc...)
Before remove Vcenter, But be sure that your ESXIs are right licensed
You can proceed by shutdown your Vcenter :-) for see if everything works fine.
The VMs are running on your ESXi Hosts and not "in" vCenter. So verify if you have the login credentials of all of your ESXi hosts can can manage them trough the browser based "Hostclient" (https://youresx/). If so you can disable HA, DRS and maybe other features the former Admin maybe have enabled within the Eval period by using vCenters WebClient. After that you can simply shutdown the VCSA VM. If there is a computer Object of your VCSA in your Windows AD you can remove it as well. Cleanup DNS and your done.
What kind of license runs your ESXi hosts?
Management workload and virtual machine workload in the vSphere environment are two different aspects, so you can easily remove the vCenter Server as the primary management component of virtual infrastructure without concern about VM interruption. Just as the other experts mentioned, check the following settings:
1. Cluster configuration if you have, especially HA & DRS settings
2. vSphere distributed switch if it's configured (VDS is ready to use if you provide the vSphere Enterprise Plus license for your ESXi hosts)
And also, check the configuration of the Backup solution that you have. Is it connected to the vCenter or directly to the ESXi hosts?Please mark my comment as the Correct Answer if this solution resolved your problem
..and in adittion to what has been mentioned above you will probably need a free license for the ESXi host in order to manager your VMs. It it's currently running with an expired license you will not be able to power on any VMs if they stop running.
You can find such a license here: