You seem to have black accents in the room so I went with black and also because you already seem to have different wood species in the room. You also need something with more substance not skimpy looking. You can also improve your accent pillows filled with feathers so that they can be propped up on the sofas not lying down.

If you do not know like it or not then better to return it and get what is really appealing to you. As for round table is not very bad with everything square or angled in room. It brings some balance.

I would return it and the end table. The end table is a great idea as it’s the most convenient for 2 prime end seats. But it should be bigger. Round would be fine, but filling the space a bit more. If there’s room for annothe end table, I’d do that too, but not if it crowds pathways.

If you really need a coffee table, I think not round. Not because of round + rectangles per se, but as noted above, it’s not as usable until the round is too big.
You could try rectangle, oval, or that type of linear double- round / nesting table set. Tempered glass could be good unless not good for kids.

It does look dinky - and where it is now, can anyone comfortably reach it when seated?

Wondering if a mockup in paper might help you figure what's most comfortable in re: shape/size? A tape measure is so helpful for things like this.

I think it’s too small

The color is fine tho

Nice color. Too small. Sit on the sofa with drink in hand and see if you can place it on the coffee table easily. Now do it from different locations sitting on both sofas.

Something with black feet will coordinate with your other pieces.

An oval glass table will be more user friendly.

It’s too small and too light. This room needs some earth tones- maybe metal or black legs with a wood top, rectangular.