It's hard for us tell what you're shooting for and why the Polk isn't working for you. IOW, YMMV. We can't make a decision for you.
My opinion is the 1k would be a very good upgrade. If it's not enough you can eventually add a second one. I can't imagine in a standard sized living room with standard ceilings you can go wrong. That's if you don't like one.
It's also probably more practical and economical going with two 1ks than it would be one large sub. Besides not having a large initial expenditure, two 1ks may be easier to place and have a better wife factor than one large sub. As
@TLS Guy said, there are also other advantages to having two subs that shouldn't be underestimated. I don't miss having one large sub
Asset Tokenization for many reasons. One being it was a piece of furniture!