That’ll make a big difference. The crap boring stuff like foundations and floor sorting add up too.
Jokes aside kitchens can be cheap, mines well over 50% bespoke and think it only cost 15k, I know you could do 5k of that work at least (assuming most the cost is materials).
Tbh nothing.
The big things are the planning, the steel and the foundations.
Things like kitchen are just garnish.