Unity.Collections / NativeContainers and DotNetStandard / DotNetCore

I support cross-platform utilities and services used in unity and a server environment. I am wondering where I need to 'make my cuts' so that I can continue to have a shared cross-platform solution while using the new systems coming out of unity.

I have my own concurrent queue and 'NativeContainer' (unsafe buffer) implementation for offloading work onto a deserialization thread. Will I be able to replace these with the official unity implementations? If so, what .net framework does it target (DotNetStandard 2?)

I have a dedicated thread for reading from the socket. This is a long-running task. Could I and should I replace this with a long-running job. That is to ask, can I run the job system without the unity runtime?

Lastly, ECS itself. It would be neat If I could have my simulation model could run on a server without the client-engine runtime.