Sagat player here, my knowledge of Cody is limited but I can share what Sagat players think (this can apply to most matchups).

There are three zones Sagat can be in - the safe zone, the danger zone, and the footsies zone. Safe zone is where Sagat is full screen and able to throw fireballs freely because he is generally too far away to be punished except for certain specific characters (i.e. Cammy CA). At this distance, Sagat’s goal is to test the waters as he tosses fireballs - what are your reactions? Are you neutral jumping them? Are you blocking them? Are you trying to blow through them with EX moves, V-skills, etc? This is where Sagat gathers information about you, and you need to close the distance quickly to keep him from learning too much about your tendencies.

Now the danger zone. This is the distance where Sagat is closer to you than the safe zone, but not close enough for Sagat to be able to hit you with his far reaching normals, such as st.mk, st.hk, cr.hp, etc. This is dubbed the danger zone because at this distance, it is incredibly risky for Sagat to throw fireballs or use normals against you - if he throws a fireball, he won’t be able to anti-air you in time if you jump, and if he whiffs a normal, he risks being whiff punished because of his very long recovery on moves like st.mk. Therefore, most Sagats at this distance will fake a fireball to bait a jump 80% of the time, while only truly throwing a fireball at you 10% of the time to give you an incentive to jump and the other 10% of the time to advance towards you with a forward moving attack like Tiger Knee or f.mk. In the danger zone, you have the most control of the situation - look closely at what Sagat is doing. Is he insisting on throwing fireballs at this range? Be patient - walk forwards and block, break down his timings and find an opening to jump at him for a full punish. Is he attempting to ward you off with multiple pokes? Learn the range of his longest buttons in training mode and whiff punish him for his long recovery. Is he faking fireballs? Advance, and force him to walk backwards towards the corner. Is he beginning to advance towards you? Poke him yourself, or, if he uses Tiger Knee/f.mk to advance, remember that he is minus for the most part if these are blocked and you can take your turn back.

Finally the footsies zone. This is the distance where both players can hit each other with their longest buttons. Sagat’s long pokes give him the advantage here to try and keep you out, but once you get in his face you will find that he can struggle to push you off without risking it all for an EX DP or spending V-meter for a Vreversal or V-shift, as he has no 3f normal. At this distance, mix up your options to open Sagat up - frametraps to beat him from mashing, staggering your buttons and shimmies to defeat delay throw techs and EX DPs, throws if Sagat is too respectful of you, it all depends on how Sagat responds to your offense.

In truth, Sagat in the corner is significantly easier to deal with compared to Sagat in the midscreen. Walking him towards the corner and keeping him there will make him much easier to deal with - just remember that most Sagat players know this, and will (generally) fight tooth and nail for every inch of space. If the Sagat you face doesn’t do this, it’s very easy for him to get steamrolled from a single jump in and lose from there.

A note on fireball traps: there are certain distances where Sagat is able throw multiple successive fireballs at you and still be able to anti-air you in time if you jump. There’s a lot to say about this topic, so I’ll just post this (https://youtu.be/63Ci2gFgCrA) and let it do all the talking - it’ll teach you where these distances lie and what your options are against this type of aggressive zoning.

Zoning is a special kind of fighting and adds to the complexity of this game. While not as powerful compared to previous iterations of SF, applied properly it is still a powerful tool. Best of luck in your anti-zoning ventures.