Hi,
Backup the VM by shutting down the VM then copy the whole folder package to alternative storage.
The VM can be a single disk or split disk as you mention. Depending on the VM disk size the split disk can be over 4GB in size.
My suggestion is to use split disk as it is much easier to manage and there's less risk of things going wrong.
Yes exclude the VM from time machine as time machine only backups complete files (so your TM backup will fill up quickly) and TM backups are unreliable for VMs.
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Wil