Unlimited Career Change Starting From Mechanic

This is the 40,000th year that the Empire has ruled the Milky Way. The glory of the Great Crusade has long been lost in the dust of history. Su Yu traveled through time and opened his eyes to see the ruined planet in front of him, with a confused look on his face.
On this planet, there are extremely dilapidated war machines that stretch for thousands of kilometers, giant alien beasts whose roars can shatter mountains and rivers, and radioactive beasts that can cause further damage to the surrounding environment just by moving -
There is everything here, but there is no hope.
Whether he wanted to or not, Su Yu, who had struggled to survive for three years and was inevitably infected with radiation sickness in the end, seemed to be one of the desperate people.
Until his career panel, which allows unlimited career changes, was finally opened.
"Ding!"
"It has been detected that the host has met the prerequisites. Do you want to take up the occupation · [Mechanic]?"
"After completing the occupation, you can gain professional experience from daily maintenance, recycling, and assembly of mechanical creations, and improve your professional level. With each upgrade, you can get an increase in physical fitness..."
Looking at the old gun parts piled up in his repair room, Su Yu's eyes lit up like never before!
Many years later, at the core of the empire, at the highest point of the Terra world, the mechanic from the ruined star, the ghost shadow blade of the dead wilderness, the restarter of the giant god weapon plan, the governor of the broken star field, the master of mechanical ascension, the highest throne of the forging world, Su Yu looked at the torrent of steel gathering below and waved an order!
[Our goal is to make the (second) (crossed out) empire great again!】