Based on my experience expect this.
ESXi itself reinstall with the hdd's connected to storage.
It should detect the drives have the VMFS filesystem, and choose to install preserving the filesystem.
When I did this I still had to manually mount the filesystems in the UI, but once done it was persistent across reboots.
Once this is done you need to import each virtual machine manually. Once imported, if the path has changed to the datastores you will need to configure each virtual storage within each VM, point it to the VMDK files. Also make sure the Virtual networking is assigned to the appropriate physical NIC.
When you first start the imported VM you may be prompted about the import, choose the option that clearly states it is "not" a copy, then things like the MAC for the virtual NIC will be preserved.
Changing things like board vendor ESXi is fairly tolerant, when I migrated my ESXi from intel i5 750 platform to AMD ryzen 2000 platform, Most of my VM's once fired up "just worked" even the windows VM. The reason been although the physical hardware has changed, the emulated hardware is the same, the only component that changes is the CPU really due to the passthru but intel/AMD are both built on the same feature sets so shouldnt be compatibility issues.
So the gotchas are the drives needing to possibly be reassigned to their VM's, and NIC MAC addressing if you select the "copied" option by mistake on VM startup.
If you got an exotic virtual switch configuration that will likely need to be reconfigured as well, essentially VM's themselves and their storage should be intact but any configuration outside of them not.
