فَلَا يَلْزَمُ تَكَثُّرٌ فِي الذَّاتِ، وَلَا تَعَدُّدٌ فِي الْقُدَمَاءِ وَالْوَاجِبَاتِ
This does not entail a multiplicity in the essence or several eternal and necessary beings.
Knowledge, power, and life are distinguishable in meaning but subsist in the one divine essence. If each were asserted to be a separate deity, plurality of necessary beings would follow. That, however, is not what affirming divine attributes claims.
The distinction between attribute and independently subsisting being is decisive. Denying multiple gods does not require denying meaningful perfections; affirming perfections does not multiply God's essence.