This is the Dumarest series by E. C. Tubb, which was also the answer to the question Identify series of books about a hero chasing a body switching potion between planets.

From Wikipedia:

Dumarest of Terra is a 33-volume series of science fiction novels by Edwin Charles Tubb. Each story is a self-contained adventure, but throughout the series, Earl Dumarest, the protagonist, searches for clues to the location of his home world, Earth.

The stories are set in a far future galactic culture that is fragmented and without any central government. Dumarest was born on Earth, but had stowed away on a spaceship when he was a young boy and was caught. Although a stowaway discovered on a spaceship was typically ejected to space, the captain took pity on the boy and allowed him to work and travel on the ship. When the story opens in The Winds of Gath, Dumarest has traveled so long and so far that he does not know how to return to his home planet and no-one has ever heard of it, other than as a myth or legend.

[. . . .]

Earl Dumarest, the protagonist of the series, is a galactic adventurer, sometime bodyguard, mercenary, gladiator, prospector, hunter, gambler and starship jack of all trades. Dumarest, as he is most often referred to in the books, is on a quest to return to the lost planet of his birth amongst the diverse and disparate worlds of the milky way galaxy. His home planet is Earth. In all of the books the notion of there being a planet called Earth is laughable to most of the people he meets, and for those who have heard the name, it is only as a myth from the deep past often referred to alongside gamblers' paradises such as Jackpot, Bonanza and the mythical El Dorado.

This is the Dumarest series by E. C. Tubb, which was also the answer to the question Identify series of books about a hero chasing a body switching potion between planets.

From Wikipedia:

Dumarest of Terra is a 33-volume series of science fiction novels by Edwin Charles Tubb. Each story is a self-contained adventure, but throughout the series, Earl Dumarest, the protagonist, searches for clues to the location of his home world, Earth.

The stories are set in a far future galactic culture that is fragmented and without any central government. Dumarest was born on Earth, but had stowed away on a spaceship when he was a young boy and was caught. Although a stowaway discovered on a spaceship was typically ejected to space, the captain took pity on the boy and allowed him to work and travel on the ship. When the story opens in The Winds of Gath, Dumarest has traveled so long and so far that he does not know how to return to his home planet and no-one has ever heard of it, other than as a myth or legend.

[. . . .]

Earl Dumarest, the protagonist of the series, is a galactic adventurer, sometime bodyguard, mercenary, gladiator, prospector, hunter, gambler and starship jack of all trades. Dumarest, as he is most often referred to in the books, is on a quest to return to the lost planet of his birth amongst the diverse and disparate worlds of the milky way galaxy. His home planet is Earth. In all of the books the notion of there being a planet called Earth is laughable to most of the people he meets, and for those who have heard the name, it is only as a myth from the deep past often referred to alongside gamblers' paradises such as Jackpot, Bonanza and the mythical El Dorado.