Tolkein likely used Frodo and the ring to explore the Christian problem of evil. However there is, as spiritual beliefs tend to echo, an eastern interpretation of Frodo’s journey.
The ring from this view embodies desire. Desire as the Buddah says is the root of all suffering. The ring is an object desired one and above all by men and other races alike within Middle Earth. The ring has caused generation upon generation of suffering namely through war but also to individuals who have come across it. We see in the figure of Gollum that the ring can become the only thing the self desires, everything else becomes meaningless beyond the barest of self preservation. Gollum lives a life of abject misery enslaved to his own desire.
Frodo in destroying the ring is attempting to destroy his own need for desire and therefore his ego as without ego there can be no desire. He volunteers for this task willingly and thus sets off on his journey towards enlightenment. This journey is one fraught with violence, starvation, long forced marches and the ever present threat of death. Those who willingly undertake a life that abstains from sensual pleasures and turns to practices such as fasting, daily marching and flagellation in order to achieve enlightenment are known spiritually as Ascetics. This path of Asceticism was the first path the Buddah took.
Yet when Frodo finds his way to Mount Doom to destroy the ring he fails. He cannot let go of desire and clings on to the ring instead. Despite the ascetism Frodo underwent his ego prevails. It is only in the act of Gollum, fuelled by his own desire, biting off Frodo’s finger then leaping into the flames for the ring that it is destroyed. We see that relying on the self to destroy the self is futile, like trying to taste your own tongue. It took an act entirely out of Frodo’s control to destroy it. The destruction of the self is inevitable either through death or enlightenment. Gollum’s body dies and with it his self whilst Frodo in seeing the destruction of the ring witnesses the destruction of desire itself and in that moment becomes free.
Upon returning to the Shire Frodo is disconnected from his fellow hobbits. His desire has gone and with it the illusion of the idyllic life in the shire he once desired has gone too. He has achieved enlightenment but in doing so realised there is nothing to return to for the Shire never existed and neither did Frodo. The trope of the heroes journey is subverted as there was never a hero to begin nor any need for a journey.
Frodo leaves Middle Earth and joins the Elves to become one with the eternal consciousness that the mythical realm of Valinor, the undying lands, represents.