Identifying a "finding Earth" series of SciFi novels

Question

I am trying to remember a SciF series of books I started reading in my early to mid-teens (1980-86) where the main character was searching for humanity's mythical home planet Earth, which I never did finish.

These were generally paperbacks I borrowed from the library or picked up in 2nd hand book shops.

The main character (male) was a mercenary who made his way from planet to planet financing his space fares by taking various contracts, generally each novel's main plot involved a single contract, but with a larger story arc of searching for humanity's lost home planet.

Unique things I remember about the series;

• The main character tended to wear a one piece combat suit, like chain mail covered in some kind of polymer plastic.
• He was a skillful knife fighter.
• Interplanetary travel took time, rich passengers took drugs which slowed down their perception of time and aging. Slow-time?
• Each planet had a shanty town around the spaceport in which lived unfortunates who could no longer pay for passage off world.
• There was a religious order who fed these unfortunates at the cost of brainwashing them against violence.
• Most characters don't believe in the one home world myth, due to the number of races of human.
• At one point the main character gains the spectrum fingerprint of Earth's sun.

Some vague plots I remember from the series;

• Searching for immortality fungus on a world overrun by fungi.
• Hunting giant lizards for gems that grew in their brains.

Answer 1

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.