Basically in spirituality, we do believe that God is omnipresent and within us. God is present in us as Tatva.
We have different forms of the Ultimate Power, which also represent different states within us. For example, when Shiva Tatva is active within us we are quite detached, peaceful, compassionate and stable. Bhairava Tatva is about fearless nature, then Shakti Tatva which keeps passionate and active. Similarly Vishnu Tatva which focus on purity, calmness etc. Then there is Indra Tatva which makes us ambitious, the ones who want luxurious life and are materialistic have Indra Tatva active within themselves.
So when it comes to Brahma Tatva, it is active in each and every individual by birth, Brahma is the creator of the material world, so we are automatically his manifestations, we are by default in the state of Brahma and so we don’t have to worship ourselves or our current version, we need upgrade, upliftment. Therefore we do not worship Brahma as primary deity, we worship the Param Tatva which is Shiva, Vishnu, Shakti etc. in order to become one with that Parbrahm Param Shakti, we are already one with Brahma being his design, but aim is to go above this layer of Maya which separates us from the Ultimate source. Brahma won’t grant moksha, only Shiva/Vishnu/Shakti can grant liberation.
So we are already the reflection of Brahma himself.
Now coming to the Puranic texts that exactly mention why Brahma is not worshipped, these events in Puranas are not random stories but they do highlight different aspects of life.
So once Brahma had an argument with Bhagwan Vishnu since he believed that he is Supreme, however Vishnu knew that Brahma had actually manifested from his navel. Later, Vedas too declared Bhagwan Shiva as the Ultimate. But Brahma refused to accept it, in order to bring a solution, Shiva asked Brahma and Vishnu to enter his body, he took the form of a pillar.. The one who would find the origin or end point of the pillar would be declared the winner. Vishnu took the form of boar and went downwards to find end point while Brahma took the form of a swan and went upwards to find origin.
While Vishnu accepted that the pillar is infinite, Brahma used his powers to make the Ketaki flower speak in favour of him, expecting that he is the winner and Vishnu has lost.
Then Shankar Bhagwan appears from the fire pillar, praising Vishnu Bhagwan for his honesty despite participating in the compition and declared that he will be worshipped everywhere. However, Shiva then cursed Brahma for lying about finding the origin point.
From the wrath of Shiva, from his the middle of his brows appeared a fierce deity, known as Bhairava who is none other than Shiva himself but because of maya he appears differently.
Kaal Bhairava chopped off Brahma’s fifth head which represented the ego, arrogance and other negative traits, by this he enlightened Brahma. However, this also meant that he won't worshipped as the primary deity, he can be worshipped along with Shiva, Vishnu etc. but not as primary deity.
After helping Brahma to overcome his ego (that act wasn't for punishing or humiliating), Shiva forgave Brahma on the request of Vishnu (who again is not different from Shiva.. Mahadev and Hari are one).
This was Lila (divine act) to teach us a lesson that we create our own illusions and because of that we have ego and other traits. Also, being truthful is important even if you lose, don't cheat, never do that to win.
Hence, we don't worship Brahma, with whom we already are one. However, it is not a sin if worship Brahma, it’s not like Shiva would get angry if we worship Brahma, but there won't be a requirement to adore the existing version of ourselves, Brahma represents the entire creation, but for upliftment, we worship the higher state of consciousness. However, Brahma being the creative aspect of the Ultimate, he is an integral part of Trinity, hence very significant in Sanatan Dharma. He is the first Brahmin, the best devotee form of God, the greatest when it comes to reciting Vedic mantras or glorifying the other primary forms of God.
Jai Brahma 🙏Jai Vishnu 🙏Jai Mahesh🙏