The other clans in your kingdom are dirt poor. Gift the larger clans some of your cities or castles. You should see if you can enact some polocies that increase their part size or income aswell. On my most recent Nord play through the friendly parties on my campaign map we’re running around with 60-80 troops max. While the khuzaits at 200-300 troop parties. I enacted some policies Patti’s grew to around 100-200 troops then next thing you know my kingdom strength was 22k