Periodically wipe and restore your phone from scratch or a known clean image, periodically change your number. Donate to Citizen Lab, EFF, Freedom of the Press Foundation, Amnesty encouraging their investigative and advisory work. Write to your representative asking for stronger regulation of the industry and sanctions against the rogue companies and their staff.

So in practicality, not a lot directly.

Do not use a smartphone seems to be the only answer. NSO seems to have the skill and resources to keep that pipeline of 0days going.