@SPG ,
Based on your description, it's recommend to go with one license.
As one of these licenses is business account, the another one is personal account, different licenses of Microsoft 365 on one computer is easier to cause unexpected conflict.
Besides, Microsoft 365 Business Premium has more services than Microsoft 365 Personal, such as the Team and Exchange, so I suggest you use this license of Microsoft 365 Business Premium.
If needed, you may run a "virtual machine" on Mac, then using the associated account of Microsoft 365 Personal to install and activate Office.
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