If Hitler hadn't followed their advice would the outcome be better or worse than OTL Citadel?
Not necessarily, although the possibility is there. To start with, it is certainly
possible that Hitler might have overruled his generals and adopted a defensive posture in 1943. He'd certainly overruled them in the past on key decisions but always in favour of attacking when they counseled caution, so it would have required quite the shift in his outlook.
Now as to whether a defensive posture in the East would have inevitably resulted in things going better for the Germans... well, Generals like Guderian accept this
a priori, but the reality is that the Germans did an atrocious job of predicting where Soviet offensives would fall, and were always scrambling on the back foot once the Red Army seized the initiative. While the German offensive plan did expend a proportion of German strength, it also delayed and weakened Soviet offensive forces and channeled their attacks into areas of German strength. The defensive preparations the Soviets committed to Kursk for example precluded them launching major offensive operations elsewhere from March until July. Given that the Russians actually had significant superiority in forces around Kursk in March, its entirely possible that if there had been no threat of a German offensive they would have attacked much earlier, and with success, starting a major push west months before it happened historically. It's also important to note that without Citadel the German panzer formations might have been stronger in these battles but it has to be realized that German panzer losses in Citadel were not catastrophic (only 320 tanks lost), and without Citadel the Soviet tank armies would
also have been stronger, and would, in fact, have likely attacked much earlier in the spring of 1943, when the Panzer formations were still rebuilding. Moreover, it is also important not to overstate the impact of Citadel. The losses both sides suffered in the following counter-offensives and the Dneiper when the Soviets went onto the offensive dwarfed the casualty totals for that one-and-a-half-week long offensive. Thus it has to be considered that things might also go
worse for the Germans if they let the Russians have free reign on where and when they strike. Possibly much worse.
In short, while it is possible that Soviet offensives absent Citadel in 1943 might go better for the Germans (the Soviets still had a lot to learn and still made mistakes, especially tactically, that hampered their offensive ability), it also could go just as badly as OTL for the Germans, if not even worse.