Nothing. The idea of sacrificing everything to build a business is extremely dated and unrealistic; it is rooted deep into hustle culture and toxic productivity. Beyond a certain point, work becomes ineffective. Taking breaks, recharging with hobbies, indulging in relationships, and focusing on yourself are 100% some of the best ROI decisions you could possibly make in building your business.
I am willing to sacrifice nothing, and have sacrificed nothing (other than some money). There is no point to success if you had to lose everything to gain it, and there is no point to life if you don't live it.
The Art of Living: Peace and Freedom in the Here and Now by Thich Nhat Hanh.
One of the greatest books I've read.