ignobleone wrote: If sense-based perception exists in the 1st jhana, then you might have different interpretation of kāmasaññā. What do you think kāmasaññā means?
It's just the selective recognition (saññā) connected with sensual desire (kāma), as explained in the Atthakatha:
Kāmapaṭisaṃyuttā saññā kāmasaññā. Byāpādapaṭisaṃyuttā saññā byāpādasaññā. Vihiṃsāpaṭisaṃyuttā saññā vihiṃsāsaññā.