Deck is not bad, but needs some work with the mana base. In order to reliably cast a spell on turn 2 with a single color in the casting cost you need the a minimum of 13 of that color. You have 13 Blue, 14 Red, and 11 White sources. This means you'll have trouble casting
Seal Away on turn 2. To cast a double blue spell (
Sinister Sabotage) on turn 3 you'll need 19 blue sources. One turn 4 you need 18. There is no way you can reliably counter something on turns 3 or 4 in your build. That's why most Jeskai lists are running
Ionize instead of
Sinister Sabotage, because there is no way to make the mana base work. To cast
Settle the Wreckage on turn 4 you need 18 white sources.
You should run a minimum of 26 lands for control ( a lot of lists are running 27), especially if you want to reliably cast Teferi on turn 5. There is not room to run the utility lands in 3 colors unless you make some concessions with the rest of the deck (with the next set, you'll have
Hallowed Fountain to help with the double white spells). Some changes I would suggest to make the deck more reliable is the following:
Lands:
4
Clifftop Retreat4
Glacial Fortress3
Island2
Mountain1
Plains4
Sacred Foundry4
Steam Vents4
Sulfur FallsThis gives you 15 Blue, 18 Red, and 13 White sources. Instead of
Sinister Sabotage run
Ionize. In place of
Settle the Wreckage run Defeaning Clarion and
Cleansing Nova. You may run into issues with double white on turn 5 with
Cleansing Nova, but it will be a lot more reliable with this mana base having additional white sources and being a turn latter than Settle. Clarion should clean up a lot of the early game stuff you don't want hanging around to allow you to get later in the game to clean of the scragglers with the
Cleansing Nova.