No offense but i think you play bad the match up because it’s in Adon favor , probably 6-4 and i think i’m not the only one to think that but he got nice buffs in Ultra.
Fireballs are not really a problem for Adon , if the Gouken wants to zone with medium fireball , focus them , zone with the roundhouse to beat the startup , keep your meter to use the ex jaguar kick , jaguar tooth is useless against him.
Adon walks fast , you don’t need to rush him , if he’s a meter , in theory you cannot jump , like you said the ex tatsu is a really good anti air , just be patient , do nothing can be good sometime , the other player can do a mistake during this time.
He if wants to zone with his normals , mainly his far hp and his sweep , you can wiff punish the first with your far hp and beat it with the roundhouse and against his sweep , use the medium or high jaguar kick and crouch mp to wiff punish.
But it’s not free , like you say his damage output his huge , he can easily safe jump Adon and he can be tricky to anti air , do a jump forward mp or hp to beat his dive delay and to anti air his air focus with less risk than the rj.
Normally you shouldn’t strugle against a fireball zoning character with Adon.
There is a ft10 between GamerBee and Desora , maybe it will help you even if the matchs are in one way , GamerBee played aggressive with ultra II.