There's a disconnect between how economists use certain terms as well-defined technical jargon and how non-economists adopt them colloquially.[0] This leads to a lot of confusion when people try to discuss economics without understanding the precise meanings of the terms at play.
For the rest of this comment, I'm going to use the economic meaning of these terms, because there is agreement among economists about what "growth" means (though not how to accomplish it).
> Or do we give up the expectancy of a better life for everyone if we give up economic growth as we know it?
Yes, by definition. It would be impossible to have "a better life for everyone" without economic growth. "A better life for everyone" is economic growth, by definition (the creation of more value - whether tangible or not - given access to the same limited input resources).
> Is is possible to have increased leisure/increased standard of living/increased health/decreasing cost of living over time
That is considered "growth" to an economist, yes.
> without having an incerase in GDP and an average positive return on capital?
In theory, yes, but it turns out that an increase in GDP is so highly correlated with economic growth empirically, as well as so intrinsically linked from first principles, that they are usually used interchangeably in most discussions.
There are a few degenerate cases in which an increase in GDP does not actually correspond to economic growth, but they're pretty esoteric and not broadly applicable.
[0] As an analogy, imagine a bunch of non-programmers debating a CS paper about 'complexity' of an algorithm, and using the term 'complexity' to mean by their ability to understand how it works. That may be a relevant metric, and it may even be related to the technical use of the term 'complexity' (complexity class), but it's not really comparing apples to apples even though it's using the same word.