Well that really depends on what you are going to do with it. Difference between 10-bit and 8bit-FRC is that
8bit-FRC really has a display range 8bits per chanel ( 256 shades ) rather than 10bit per chanel ( 1024 shades).
8bit-FRC simulates the remaining intermediary channel shades by strobing between the two closes shades from 8 bit gradient (256 shades).
Now for normal use, that's perfectly fine, the difference is marginal.
However if your main usercase is color accurate tasks like DTP, colorchecking, preprint etc. this is not the way go.
But seeing you're looking at 165hz monitor, this is clearly not the case.
The short answer is no, you can't run 1440p 165Hz 10bpc from DisplayPort 1.2 as this resolution and refresh rate at 8bpc is approaching the limits of DisplayPort 1.2's bandwidth. You'd have to go down to 120Hz to use 10bpc.
However unless you deal with or have a lot of content that's encoded in 10bpc, it doesn't matter if you use it. Also using 8bpc over 10bpc isn't going to make things less colorful, but it does mean the chances of color banding are higher in some cases.