Most people who get 30k+ points use frames and/or necramechs that have all been kitted out and min/maxed to hell. so dont be upset if you can get over 2k points a run, just keep trying at it and tweak your builds to whatever play style you like! Ive found I spend 90% of the mission in a necramech, whether its my own or the randomly spawned ones so I focus less on the frame aspect of the event, having ideal mods for the mech/archgun is a huge portion of the event. the wiki has great locations on how to farm for necramech mods and which ones exist here.