Do the specific adapters that you have specifically support 4k60hz 10-bit?
The 2018 MBP supports
Up to two displays with 5120-by-2880 resolution at 60Hz at over a billion colors
Up to four displays with 4096-by-2304 resolution at 60Hz at over a billion colors
Thunderbolt 3 digital video output
Native DisplayPort output over USB‑C
VGA, HDMI, DVI, and Thunderbolt 2 output supported using adapters (sold separately)
"at over a billion colors" would be 10-bit.
8 bits per color channel: 16,777,216 total colors
10 bits per color channel: 1,073,741,824 total colors
12 bits per color channel: 73,876,521,536 total colors
14 bits per color channel: 4,398,046,511,104 total colors
16 bits per color channel: 281,474,976,710,656 total colors