This is fine. ESXi 6.7+ come with a new HTML5 web interface anyway that is way better than the standalone client.
Posting the response from the Royal team:
"We are not able to implement support for VMware's free Hypervisor, because VMware restricts certain API actions - we're not making this limitation, and we're also not able to bypass this. Such limitations also apply to well-known backup solutions like Veeam. There's unfortunately nothing we can do against. To be more specific: When running with a free ESXi license the API is only read-only and therefor it is not possible to request the required Remote Console API Tokens to establish a console connection and such stuff. Read more about here: https://serverfault.com/questions/884743/free-esxi-6-5-and-api-support"
Jiri Brejcha
VMware ESXi is now supported, but TSX only can list VMs deployed on the free VMware Hypervisor and show their status (on/off). It can't control them or apply any changes.
Basic controls (start/suspend/shutdown) of those VMs would be great.