You care about the person. That is exactly the problem. If you did not, "wishing you all the best" would be fine, you would send it, and the day would move on.
But it is your sister, or the colleague who covered for you all year, and the generic version feels like a small betrayal. So you stare at the message box, write something, delete it, and eventually send the generic version anyway at 11pm.
What makes a greeting land is never eloquence. It is specificity - one true detail about this particular person that could not have been written about anyone else. AI cannot supply that detail, but it can build a warm, non-clunky frame around the one you give it, which is the part most people find hard.
This prompt returns two versions in the style you pick, so you can choose rather than compose. Run it in the AIMIKA chat in Text mode.
You get two versions in the style you pick - heartfelt, funny, in verse, or a toast to say out loud - so you can choose rather than compose. Both avoid the greeting-card register that makes a message feel like an obligation discharged.
One thing the prompt cannot do is supply the detail that makes it land. It needs one true thing from you: the renovation they finally finished, the running joke, the year they had. Give it that and the result sounds like you wrote it. Give it nothing and it will sound like a card, because that is all it had to work with.