Issue with LWRP deprecation

I wish to make a complaint here.
I just recently spent a year making a video filter app, utilizing the fantastic ShaderGraph and the LightWeight render pipeline.
Now after progressing to the Unity 2020 ( in order to take advantage of its corrected MacStore signing procedures ),I find that the shadergraph has been discontinued, and the lwrp has been replaced with the universal render pipeline.
So now my project is totally broken in terms of future development. All the custom shaders that I artfully made are now unusable. That is a considerable amount of work for me to now throw into the bin. All my custom shaders were being dynamically tweaked.And now they cant be.
And i just know that next year or the year after, the universal pipeline will be discontinued in favour of something else. And all projects will have to be continually rebuilt AGAIN.

No, for the most part it's a rename. All your shader graphs should work exactly the same...

Basically if you upgrade your project it's a matter of just making sure the graphs recompile and any code is renamed. Also 2020 version is a little premature to be using (although I am, but I'm not deploying with it yet).

Upgrading from LWRP to URP is fairly trivial as it was just a name change and the sort of feature evolution we normally get between major pipeline versions.

I dont know if this upgrade guide is still accurate, since it is a bit dated now, but may still help you:

What made you think Shadergraph was discontinued? Its a major part of their new era systems, it isnt going anywhere.