A few things to consider.
landlords are often on ego trips and they don’t value tenant retention. By moving out, they have to make repairs, pay a broker fee for a new tenant, have the risk of it becoming vacant (especially for 1/2 month), risk a bad new tenant. I’ve always mentioned these things why renegotiating and it tends to work in my favor.
min the post covid world where more people will be working from home will see people love out of the city. No commute, lower costs, bigger spaces. If the landlord doesn’t realize this, they’re being silly.
From your perspective, if you decide to love out you have to consider the time you’ll spend searching for a new apartment, brokerage fees, and moving expenses.
I don’t know what your rent is like but a 10% in NYC can be $500. You can always try a fixed amount. Instead of $4200 per month, how is $3900. Also, try to commit to a longer lease vs 1 year.