For sure, though I still think there isn't enough data on open-air and delta.
Anecdotally, my vaxed nephew contracted covid sitting in a garden with friends. They ordered food together, so I'm not sure if he was just a mong and shared some food or cutlery or something, or whether he really was as careful as he made out - but that could be an open air transmission. If I were you, I'd still exercise caution until there's more data.
I mean at the end of the day, even if you are outdoors, if a friend/someone is sitting/standing directly across from you and talking straight at your face from a couple feet away for a period of time, it shouldn't matter how diluted the stream is, if infected they are expelling covid particles non-stop straight at your face which you will be breathing in.
If you're outdoors at a garden/beach wherever walking past people and not having conversations with anyone, the transmission would probably be very low
since the particles are just flying around in the environment diluted by the wind.
Unfortunately the world has not created a distinction for outdoor activities between doing activities outdoors and talking to people outdoors.
But having face to face conversations with people unmasked just seems like a contagion vector no matter where you are. So yeah, having conversations with people, even vaccinated people, unmasked in the middle of a huge delta wave seems dangerous. Better to be anti-social or mask up.