You may want to run through: Unable to log in to the root account of vCenter Server Appliance (2069041) | VMware KB
This will allow you to reset the root password and lockout. After that you can modify the lockouts if needed.
do not use vcenter server appliance.
Managing ESXi without vCenter is rather difficult. I believe essentials has a license for vCenter. If not I would get it.
You may need to reinstall ESXi, but after you do so create some users so that the Administrator user is not used for administration. You should never use the root user for anything but break-glass. You should also apply RBAC. Even if you are the only admin, use a separate user to do administration. It is the best practice.
A reinstall of ESXi will not destroy your VMFS as long as you choose not to create a new VMFS. That is an important step.
Edward L. Haletky