OnePlus Devloper Preview When?
When they have given a 10.3.5, do you think they have forgotten it?
OP6 is the third or fourth priority phone now. It's more than 2 years old. You won't be getting any developer preview. Even the 7/T series don't have it.
You can expect it by Q1 2021. It was a similar time when the OP5/T got Android 10.
And please don't create a new thread for things like this. Discuss in the already available official threads.
Weekly Update 354: Hello, OnePlus 8T and Accessory Testers
by Crystal Z., 2020-09-26