Similar to Reinterpret AVC bitstream as HEVC.
Some hardware codecs support 4:2:0 for 4k but not don't support 4:2:2 even for SD, with far less data. Can you trick a codec to encode 1920x1080 4:2:2 by feeding it 1920x2160 4:2:0?
No, you can’t trick it because the chroma planes are different resolution. 4:2:2 has twice as much data per chroma plane as 4:2:0. You need to rescale. It’s like trying to trick two liters of water to fit into a one liter bottle.