Study to Evaluate Efficacy and Safety of Firmonertinib Compared With Investigator's Choice of EGFR Inhibitor as First-Line Treatment in Participants Who Have Locally Advanced or Metastatic NSCLC With EGFR P-Loop and Alpha C-Helix Compressing (PACC) Uncommon Mutations

Key Eligibility Criteria: * Histologically or cytologically documented, locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) not amenable to curative surgery or radiotherapy. * Documented results of the presence of an Epidermal Growth Factor Receptor (EGFR) PACC mutation in tumor tissue or blood from local testing. * No prior systemic anticancer therapy regimens received for locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) including prior treatment with any Epidermal Growth Factor Receptor (EGFR)-targeting agents (e.g., previous (EGFR) TKIs, monoclonal antibodies, or bispecific antibodies). * Patients who have received prior neo-adjuvant and/or adjuvant chemotherapy, immunotherapy, or chemo radiotherapy for non-metastatic disease must have experienced a treatment free interval of at least 12 months. * Patients with asymptomatic CNS metastases are eligible.