Hi:
The fastest speed your notebook's Intel® Core™ i7-7700HQ processor can run the memory at is capped at 2400 MHz.
Intel® Core™ i7-7700HQ Processor (6M Cache, up to 3.80 GHz) Product Specifications
So any memory you install beyond 2400 MHz, will bridge to 2400 MHz.
You may want to buy the faster speed memory and use it in a newer notebook in the future.
That would be the only reason for buying the faster memory, such as DDR4-2666 or DDR4-3200.
The normal CL speed for DDR4-2400 memory is CL17 and I would not recommend buying memory that does not have the standard CL speed for its class.
I don't believe that your notebook is designed to run memory with a smaller CL speed than 17.
You can not change any of the memory XMP profiles in the BIOS, so I would not take such a risk.