For me this is the best ending!!!
you need collect 13000 kuai
all you have to do is choose "i'll make more money and get everyone paid by the end of the month" on day 10 when your sister arrive


key moment:
Day 4 - security job
Day 7 - flyer job
Day 10 - sister come - "i'll make more money and get everyone paid by the end of the month"
Day 11 - inventory shorter job
Day 15 - historical downtown map opened
Day 16 - your mom sick and your sister go home
Day 17 - pay 3000 for hospital
Day 19 - pay loanshark 10000
Day 22 - promotor job
Day 23 - poke loan shark smart lvl 4
Day 27 - chef aid job
Day 28 - usher job

i think this is the easiest completion ending, but bitter story...
you need collect total less than 9000 kuai
all you have to do is choose "lets pay the loan shark with this money" on day 10 when your sister arrive


key moment
Day 4 - security job
Day 7 - flyer job
Day 10 - sister come - "lets pay the loan shark with this money"
Day 11 - inventory shorter job
Day 15 - historical downtown map opened
Day 17 - sister leave
Day 22 - promotor job
Day 23 - poke loan shark smart lvl 4
Day 24 - 1050 from your sister
Day 27 - chef aid job
Day 28 - usher job