I think Jiang Cheng is actually similar to Lan Wangji in that he also shows affection through giving gifts, though for mostly different reasons.
Like, Jiang Cheng’s demonstrably bad at expressing his feelings with words, and I also think that the most positive aspect of his own personhood, for him, is his status and power and wealth. That role he’s inherited, and the security that comes with it, are the cushioning for the festering pit of self-loathing inside him. And so his outward behaviour towards other who matter to him often manifests as spending money on them.
This manifests in a particular way with Wei Wuxian post-canon, because Jiang Cheng hasn’t lost his competitive impulse towards him and subconsciously feels his money and position give him something of an edge over this person he’s always been compared unfavourably to. Also he’s just in major “WE CAN’T LET WEI WUXIAN KNOW WE LIKE HIM” mode and so he defaults to passive-aggressively dragging him off to the tailor shop saying “you’re too scruffy, you’ll embarrass me dressed like this” and then commissioning five expensive sets of robes for him.








