After their first date, very often Susie came to the sea to meet him, if not almost every night.
Can you identify the name the bold part? Is it an adverbial phrase? Strangely, I have never encountered it before. I searched on Google, and the results contain the similar structure "if not almost", but I don't know whether any of these websites are well-written ones.
Two other questions:
"Very often" is also an adverbial phrase; is it correct to have two of them in a sentence?
I see that people often add a comma after "very often"; is it okay not to put a comma here?