If one is seeking truth but practicing yoga or Kundalini or any other practice for long years and finding them inadequate and useless quenching his inner thirst has to drop them by realizing they are only useful in preparatory stages to make him more receptive to grasp the ultimate truth and they cannot transport him to the ultimate end of understanding.
Sage, Sri, Sankara' gave religious, ritual or dogmatic instruction to the mass but pure philosophy only to the few who could rise to it, hence the interpretation of his writings by commentators is often confusing because they mix up the two viewpoints. Thus they may assert that ritual is a means of realizing Brahman, which is absurd.
In commentary to "Brahma Sutras Sage Sri, Sankara indicates:-." "The highest beatitude is not to be attained by Yoga." (Sacred Books of East Series page 298 Vol.1.) And he also says Samadhi is the same as sleep (p.312).
---this clearly indicates that yoga is not the means to self realization. And yogic Samadhi is not non dual wisdom.
The seeker has to follow up his deeper self-search and get rid of the inborn samskara or conditioning, which is present as ‘I’ or ‘I AM’. There is no need of buying reading material or hearing the sermons and running to one place to another or one guru to another or surrendering to any guru or glorifying any guru in order to acquire self-knowledge or Brahma Gnana or Atma Gnana.
Sri, Sankara says in Viveka Chudamani indicated that:-
56. Neither by Yoga, nor by Sankhya, nor by work, nor by learning, but by the realisation of one's identity with Brahman is Liberation possible, and by no other means.
58. Loud speech consisting of a shower of words, the skill in expounding the Scriptures, and likewise erudition - these merely bring on a little personal enjoyment to the scholar, but are no good for Liberation.
59. The study of the Scriptures is useless so long as the highest Truth is unknown, and it is equally useless when the highest Truth has already been known.
60. The Scriptures consisting of many words are a dense forest which merely causes the mind to ramble. Hence men of wisdom should earnestly set about knowing the true nature of the Self.
61. For one who has been bitten by the serpent of Ignorance, the only remedy is the knowledge of Brahman. Of what avail are the Vedas and (other) Scriptures, Mantras (sacred formulae) and medicines to such a one?
62. A disease does not leave off if one simply utter the name of the medicine, without taking it; (similarly) without direct realisation one cannot be liberated by the mere utterance of the word Brahman.
63. Without causing the objective universe to vanish and without knowing the truth of the Self , how is one to achieve Liberation by the mere utterance of the word Brahman? — It would result merely in an effort of speech.
64. Without killing one’s enemies, and possessing oneself of the splendour of the entire surrounding region, one cannot claim to be an emperor by merely saying, ‘I am an emperor’.
65. As a treasure hidden underground requires (for its extraction) competent instruction, excavation, the removal of stones and other such things lying above it and (finally) grasping, but never comes out by being (merely) called out by name, so the transparent Truth of the self, which is hidden by Maya and its effects, is to be attained through the instructions of a knower of Brahman, followed by reflection, meditation and so forth, but not through perverted arguments.
66. Therefore the wise should, as in the case of disease and the like, personally strive by all the means in their power to be free from the bondage of repeated births and deaths.
Sage Sri Sankara clearly indicated that: - yoga, intellectualism, scriptural mastery is not the means to Self-Knowledge or Brahma Gnana or Atma Gnana. But by the realization of one's identity with consciousness, which is ultimate truth or Brahman, freedom from experiencing the illusion as reality is possible, and by no other means.
Seeker of truth has to get rid of his doubts through deeper inquiry, analysis and reasoning on his own, to realize the fact that, the self is not the form but self is formless. Thus his analysis and reasoning has to be based on the formless not on the form. By simply go on believing and accepting whatever said by the punditry and intellectuals will not lead one towards path of wisdom. All the doubt has to be got rid of "by the sword of Self - Knowledge or Brahma Gnana or Atma Gnana." The scriptures, yoga are not necessary if one follows the inner [formless] path. Religion and yoga are not the means to path of wisdom.