Sidious's ultimate goal in canon

I think I read somewhere to Legends Sidious' ultimate goal was like to turn the whole galaxy into a giant dark side nexus and absorb all life or some very evil-ish stuff like that (or maybe I just made up everything lol). What about canon Sidious? Was his plan just to live forever and rule his empire?

It was explained in Tarkin's novelization.
Sidious wants to unlock the secret of the force and use it to reshape the universe/reality

Well that’s much better and smarter than consuming all life in the galaxy. GG Canon Sid

In Legends he wanted to become the galaxy, not absorb it.

That'd still be pretty boring honestly, what's good from becoming a galaxy?

Power is its own reward.

It's basically the same thing. Reshaping reality in his image would be absorbing/bending everyone and everything to his will.

Yeah, in canon he wanted to reshape the universe in his own image:

Palpatine would not allow himself to be sidetracked from his goal of unlocking the secrets many of the Sith Masters before him had sought: the means to harness the powers of the dark side to reshape reality itself; in effect, to fashion a universe of his own creation. Not mere immortality of the sort Plagueis had lusted after, but influence of the ultimate sort.

-Tarkin

And as we saw in Rebels, the key to achieving this endgame would have been TWBW: "It's a pathway through all time and space. He who controls it, controls the universe."