Hi @PhilZ ,
Unfortunate though it is, as per my knowledge it is not supported to access SharePoint 2019 library using UNC path if you don't map the library to a network drive. This is by design. You can submit your feedback to MS here: https://feedbackportal.microsoft.com/feedback/forum/06735c62-321c-ec11-b6e7-0022481f8472. Customer feedback is very important to us – your ideas can change and improve products for users around the world.
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