According to the release notes for VMware vSphere 8.0U3e, VMware vSphere Hypervisor (ESXi) can now be downloaded free of charge from the Broadcom support portal:
Broadcom makes available the VMware vSphere Hypervisor version 8, an entry-level hypervisor. You can download it free of charge from the Broadcom Support portal.
Next, I use my own (non-corporate) account without any SiteIDs added.
In the Free Downloads section, we can find VMware vSphere Hypervisor:

With the only one release available – 8.0U3e:

After reading and accepting terms and conditions, we can download the ISO:

After installing, the first thing we want to see is the license:

We can see that the expiration date is set to never, and the host is limited to 8-way virtual SMP, meaning that you cannot power on the VM that contains more than 8 vCPUs.

In the example above, you can see that I cannot power on a 16-vCPUs VM. However, I can power three VMs with 8 vCPUs each:

And this is the same way as it worked before. This is a suitable option for extra-small deployments, labs, and testing. For large environments, you should definitely consider purchasing VVF or VCF licenses.
Regarding the license key, you don’t need to get one as it was before. It is already installed in the ISO. According to the screenshots shared on Reddit, all downloads use the same key.