If they were dead set on doing a tax cut (unfortunately for the good of the country) at least they made it an NI cut rather than an income tax cut.
I can see a way forward for labour if they want to raise more money without straight up reversing these cuts by abolishing NI (or gradually reducing it to phase it out) and correspondingly increasing income and/or capital gains tax.
They can chalk it up as making the tax system fairer by removing the tax on which employees pay more than self employed or those with passive wealth-based income. Simultaneously they can say they are building on the one positive outcome of the previous budget.