the "que" is very strange in this sentence, I'm Brazilian...
Is it more poetic? For example, in English you might see "the surface is like that of a mirror" which sounds a bit uncommon and flowery, though not incorrect.
That's how I was interpreting it.
"A superfície do lago é como que um espelho."
Why is the "que" needed here?
For me, it shows intensity. Making the sentence without "que" makes it stronger, while without "que" it becomes a slight comparison.
So, with "que" is a stronger comparison, and without "que" is a weaker comparison?
Then the English translation should certainly include the "that of," which is one more stylish way to say it...
It's not. you can ignore it completely.
I'm not saying that this "que" is wrong (because I honestly don't know). But I know that it's uncommon and it sounds very weird. We can just ignore it or substitute this "que" for "se fosse":
A superfície do lago é como se fosse um espelho.
I have never in my entire life heard someone saying a sentence like this. The word "que" is completely unnecessary and probably grammatically wrong.
"A superfície do lago é como um espelho" would be a better translation!
In this case, "que" is not needed.