Yeah, it does need DSC for 1440p at 360hz, especially at 10bit.Its probably not needed with only 1440p, 360hz. 4k @ 240 or 350hz would need the extra bandwidth.
A quick google -
32.4 Gbps on DP 1.4 - 144 Hz at 4K and 240 Hz at 1440p
80 Gbps on DP 2.1 - 4K at 480 Hz and 8K at 165 Hz
I use Glenwing's calculator whenever I need to check if something is supported, especially because I will run custom resolutions at times too: