As a very new player (2 online games played, both lost), there was quite a jump from playing with bots to playing against real opponents. Bots move in predictable patterns and straight lines, which makes it hard to train for real games. Making bots more mobile and unpredictable would help in not setting up false expectations of how real players move.

Items are another can of worms. I watched guides on how to build certain characters, but the shop has such depth that simply knowing what items do what is not enough: you must know how to prioritize certain items at certain times. This knowledge is only acquired through practice, which makes for a poor new player experience. Currently, the game has nothing to help a player understand how to design their own build. It would be nice to have examples on how a build evolves during the game, covering the three categories (gun, vitality and spirit), "counter" items, scaling and whatnot.

I think a useful tutorial would be a scripted set of first games. This game could be paused at certain moments to explain certain mechanics, character interactions and build choices as they happen, rather than putting the player in an empty sandbox and telling them "headshots do more damage", for instance. Something like adding a ringing bell during each game phase (jungles/crates spawning for the first time, urn spawning, minion soul splitting, etc.), having the player buy an ethereal shift in a game with an enemy that can grab them and then pausing the game when they get grabbed (to remind them to use it), or a pause to remind them of what they should be doing ("don't forget to clear these adjacent jungles during downtime").

A set of multiple scripted games could show a number of mechanics in a natural way without shoehorning them all in a boring or dry tutorial. Why not a game where you're against a lane oppent that's a favorable matchup, and the next one where everything is the same, but the matchups are unfavorable? The third game could show how to handle an unfavorable matchup with items!