TPL configureawait break down to obtain the result + obsolete in .NET core?

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C#

Learning TPL library here. If I wanted to break up ConfigureAwait so I get the returned value by an async method how should I do it?
ie. Given an async method GetDto() that returns an object of type Dto, normally called as:

var dto = await GetDto().ConfigureAwait(false);

In trying to understand how this breaks down, how would I do this

Task t = GetDto();
await t.ConfigureAwait(false);
//how do I capture the returned dto object here?
//also, 

Also, is it correct that in .Net Core 3 no need to call ConfigureAwait anymore? I thought that somehow the nature of the problem is that ConfigureAwait will always serve a purpose as you would want to be able to execute the continuation block in the same thread as the async call in situations that permits such ascontinuation code blocks that have no reference to UI objects?

Thanks

What I have tried:

Task t = GetDto();
Dto dto = await t.ConfigureAwait(false); //<-- doesn't work