If you want to emphasize/de-emphasize a UI element, you can do something like was established on most GUIs 30+ years ago: make the default/safest option have a thicker border, and the secondary/de-emphasized option have a thin border. Early examples (1985 and 1991 respectively):
https://guidebookgallery.org/pics/gui/settings/appearance/wi...
https://guidebookgallery.org/pics/gui/system/features/search...
Note how immediately-obvious it is which action is the "typical". You don't even have to read the text, you could even squint your eyes or glance from a great distance and still understand which button is the one you probably want.
UI design involves trust, especially for software where people are trying to actually get something done. Making unconventional designs erodes your users' trust. Have respect for them and what you can reasonably expect them to "know" arriving at your software, and they will have an easier time and love you for it. As we can see, these conventions have existed for decades, and deviating from them warrants a very compelling reason, not just "cuz it looks neat".
What's the reason that the designer wants to nudge me to accept invitations again? I missed it.
Also, what's the difference between that and a dark pattern?
“Decline invitation” needs to be something you can do, of course, but it will be used < 1% of the time, I imagine.
I find that having buttons side by side forces me to think in a mildly unpleasant way, like I have to read two thinks more carefully because there is more onus on me to decide which is the typical action.