Water in Basement of 2-year-old house

Hey guys, We just bought our house a month ago and have gotten a ton of rain recently. The house was constructed in 2015 and has had 1 previous owner. The soil is pretty well graded outside. We checked our basement and there was water all over the floor; I wouldn't say standing water, but it was everywhere. I just wanted to see how to proceed before calling a professional.

We had radon and had to have a mitigation device installed. Stupid question: could this be the culprit? The reason I ask is that the previous owners had the basement packed full of stuff for storage and we looked everything over for water damage when we did the walkthrough.

We do not have a backup sump pump yet, but we did not lose power. I do not know the size of the current sump pump. Is it possible that the pump was undersized and could not pump out the water fast enough?