Hi,
Thanks for posting in our forum, and sorry for the delayed reply.
>>What is best practice when assigning private key permissions to service accounts that need them when the certificates are issued via a
certificate template in ADCS?
Based on my experience, I will suggest you use option “Authorize additional service accounts to access the private key” under “Request Handling”
tab to assign permission for service accounts.

>>
If I manually assign permissions to grant a service account access to the private key of a computer certificate issued via an ADCS certificate
template, will these permissions be removed when the certificate auto-renews?
As far as I know, it will not be removed.
For your reference:
https://winintro.ru/certtmpl.en/html/b0fcf6c9-bd3d-4e1e-bd94-8e306a6d2415.htm
https://social.technet.microsoft.com/wiki/contents/articles/13303.windows-server-2012-certificate-template-versions-and-options.aspx
Best Regards,
William
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