These DPI companies always make me smile because 20 years ago I was the inventor on this patent: https://patents.google.com/patent/US6182146B1/en It describes a way of doing DPI to identify protocols that are not running on standard ports. We used this for a protocol analysis product [0] that did network monitoring (for accounting purposes inside companies and led to companies discovering what people were mis-using their network connections for---hello PointCast[1]) and for prediction of network scaling needs. And all that was based on stuff I'd been doing from about 1984 [2].
Bottom line: scooping up packets is easy; encrypt your shit.