rsx is good enough for daily commute
can consider raider too for extra power

get big bike if you want to have fun
under 20k you can find used kawasaki z650 with abs, bigger than kapcai and not as heavy as d400.
still easy to squeeze through traffic also

if you dont care about abs can find old yamaha mt07, size similar to z650

whats wrong with the raider?

tried it a while ago and didnt feel anything weird

well z650 and d400 weight isnt that much of difference, but weight distribution z650 feels more flickable and lighter in that sense

make sure to test ride the bikes before you buy them, who knows maybe you'd like the d400 more than z650