Old Genshin Impact leaks have already revealed what all of the Sacred Sakura tree rewards are.
Getting to level 50 seems impossible in Genshin Impact. Of course, Inazuma isn't fully released yet, which is the reason why Genshin Impact players haven't received all of the rewards. More Inazuma islands will have more Electro Sigils for players to collect.
Once more facets of Inazuma are released, Genshin Impact players will be able to max out their Sacred Sakura tree and claim all of its rewards. Each Sacred Sakura tree reward from level 1 to 50 requires 25 Electro Sigils and the player will get their rewards once all 25 Electro Sigils are deposited for any given level.
Genshin Impact leaks: All Sacred Sakura tree rewards from Level 21 to 50
Every single level requires 25 Electro Sigils. Hence, this article will only focus on the Sacred Sakura tree levels and what rewards they offer (as it would be redundant to constantly mention 25 Electro Sigils per level).
Level 8 Electrogranum lets the Electrogranum duration last up to 25 seconds (rather than 20 from Level 3). Level 9 Electrogranum makes it so that every Electro character has 20% more DMG with Electrogranum coordinated attacks.
Level 10 Electrogranum ensures that every three coordinated attacks with an Electrogranum will make the next attack deal Electro AOE DMG.
Other than that, most of these rewards resemble the previous ones. The main difference is the type of "Billet" given to the player from 4, 14, 24, etc. If Genshin Impact players are efficient, they'll likely be in the low to mid-level 20s right now.
Level 11 Electrogranum makes it so that the player can block up to 10 instances of DMG from environmental damage. Level 12 Electrogranum ensures that Genshin Impact characters can pass through Advanced Thunder Barriers.
Finally, Level 13 ensures Electro characters deal 30% more DMG with Electrogranum AOE attacks.
Like before, most of these parallel the previous ten rewards. However, there are a few main differences. Level 34 offers a Northlander Catalyst Billet instead of a Northlander Polearm Billet.
Also, Level 40 gives the player a Dream Solvent instead of 200 Adventure Exp. Other than that, the rewards are identical to the previous ten Sacred Sakura tree rewards according to the leaks.
Level 14 Electrogranum makes it so that Electrogranum now lasts for 30 seconds. The final level (Level 15) decreases the amount of coordinated attacks for AOE DMG down to two (rather than three).
This table parallels the previous one, except Level 44 offers a Northlander Bow Billet instead of a Northlander Catalyst Billet. There is also no Electrogranum level at Level 50. Other than that, everything else is identical to the previous 10 levels.
Level 50 is the final level for the Sacred Sakura tree. All of these rewards come from an old leak, so it's possible that they can be altered in a future version of Genshin Impact.