The Verdict: Not eligible
The non-lucrative visa does not allow remote work, so it is the wrong visa for you. Take the digital nomad quiz instead; that visa is built for people working for employers or clients outside Spain.
Spain's consular guidance says it plainly: this visa is not a work permit and does not allow teleworking. Consulates have tightened on it, and working while on it puts renewal at risk.
The digital nomad visa has its own income test and paperwork, and its time also counts towards naturalisation.