BTW my iPhone X is supporting 3CA. It does not connect to 3CA all the time but keeps on fluctuating between NoCA 2CA and 3CA.
I have noticed that 3CA gives pathetic speeds in my area. This has been tested even on Google Pixel 2. The only time I have seen upwards of 60 Mbps speeds is at 4am in the morning.
And how about the speeds otherwise during day time ?