Hi @john john
PnP is supported in similar ways as other open source projects done by Microsoft with support from the community by the community
There are numerous partners that utilize PnP within their solutions for customers. Support for this is provided by the Partner. When PnP material is used in deployments, we recommend being clear with your customer/deployment owner on the support model
You can refer to following document
Supportability of open-source projects
As far as I know, you can use CSOM or JSOM to alternate pnp.
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