The Sonoma beta download seems to be Apple-Silicon only, though 2018 mini is among the supported machines.
Can I run Sonoma on x86 (2018 mini 32GB)?
Via Apple's Virtualization API's rather than a boot partition? I didn't see a link to a restore image.
(Also, would someone please add a forum tags for Sonoma?)
Not sure about 'download', but using the upgrade option (System Settings->Software Update->Beta updates macOS Sonoma Developer Beta it's installed and running fine on my Mac mini 2018 (3.2GHz I7, 32GB).
As for VM deploys, Apple's Mac virtualization API's are arm64 only (i.e., #if arch(arm64)
So the workaround is to install Ventura to an external, and update to Sonoma beta from there.