You do seem to have a knack for not comprehending the words you read. In this case I said nothing of the sort, as usual.
I'd say a small part of science is pushing those boundaries. And the result, as usual, will be that we'll have a slightly bigger observable universe. And 'tons of ideas and theories about the part of the universe which can't be observed' aren't part of that, as far as I'm concerned. People are, of course, free to hold their own opinions on that, but I count it as sci fi. In the example of a multiverse: that will not advance our knowledge about the universe any more than the question How many angels can stand on the point of a needle? Meanwhile the actual universe keeps expanding, so relatively, you might say, we'll actually know less than before. A paradox, perhaps.
The universe doesn't 'end'. And obviously, 'the universe' is not 'the observable universe'. But scientifically speaking it is. The limit of things we can have knowledge of is the observable universe. Beyond it is where the facts end and speculation begins. In the end though, we just don't know. One can try to extrapolate beyond that, of course. But we only have the one universe to extrapolate from. No ideas about multiverses or what other cosmological speculations cosmologist may think of can change that. Possibly, at some point in the future this may change. Who knows.