First off, I love that suit alone, and with the bomber! You look like a million bucks! I’m really digging the Issey Miyake vibes. I think the blazer is okay, but it’s reading kind of “corporate” to me. The bomber has swagger, and the set feels authentically you.
Setting aside all of the nonsense about this event… I think you should only keep this outfit if you feel a happy little thrill when you put it on and see the stone cold fox looking back at you in the mirror.
If there is time in the returns window, maybe let it sit for a couple of days.
The event itself… WOW. Holy . It’s not the house or the landscaping fund that’s the red flag: it’s that they’re dictating the colors their guests are wearing! These seem like some high-maintenance people. For my part, I would plead a migraine.
If you can’t politely bow out, then take charge of where you are in this situation. I say wear something bold and audacious, with some swagger. Make a reasonable gift to the landscaping fund. And make some plans for an after-event treat for yourself - maybe a late nightcap somewhere fun, or a bubble bath when you get home. Treat yourself.