The English word 'Illusion' is an inadequate translation of the Sanskrit word 'Maya' from the Vedic Sanatan Dharm of Hinduism of India.
The very conception of the Lord Bhagwan as the Creator, Preserver, and Destroyer of the universe is the result of maya.
One can know and contemplate the Personal God through this power of maya; otherwise Pure Consciousness, which is devoid of all attributes, remains unknown and unknowable to the ‘finite’ mind.
That’s exactly the reason why we need to practice Dhyaan and Saadhana to go beyond the finite as laid down step by step, by Rishi Patanjali.
Maya is an inexplicable power belonging to Brahman. It is the creative energy through which the phenomenal universe is projected.
It is only when the Knowledge of infinite Reality arises that maya completely disappears.
So, even if you start slow, practice steadily on your ‘finite’ path to transcend beyond the finite and discover the ‘Infinite’ because, That’s what you are.