Why the Dot OS Unofficial Build was deleted?
The reasons mentioned by the developer @alwaysangry are as follows:
1. The build was stable with no bugs at all.
2. I deleted it because I wanted to give to the people who are most active in the community and they got it too... ☺️

Sounds like Dot OS Unofficial Build was like limited time grab, which I think some or many people missed it.

🆕 Pixel Extended 3.2 Android 11 OFFICIAL for OnePlus Nord
📅 Release Date: 16/09/2021
👨‍💻 By: @alwaysangry

📝Changelog:
• Source Changelogs
• Updated Firmware to OOS 11.0.5.5
• Updated Kernel to OOS 11.0.5.5
• Updated Vendor to OOS 11.0.0.5
• September security patch

Donate:
UPI: raavimanikanta6595@oksbi

According to people over Oxygen Updater reported that Oxygen OS 11 Open Beta 6 was the last Open Beta Update for OnePlus Nord.

Read more in the article linked below:
https://oxygenupdater.com/api/v2.6/news-content/279/EN/

🆕 Pixel Experience Android 11 OFFICIAL Regular/Plus Editions for OnePlus Nord
📅 Release Date: 19/09/2021
👨‍💻 By: @kakatkarakshay

📝Changelog:
• Fixed Bluetooth Audio on Incoming Calls

Donate:
• Check donation info here

Quick Update about upcoming video:
I have cancelled LOS 18.1 Review as it was taking too long to actually test and release it's review. Plus I am suffering from some health issues recently, so I can't speak much for longer time (which is necessary for videos).
However, by next week I will drop a review on channel.

🆕 AOSP Extended 8.6 OFFICIAL for OnePlus Nord
📅 Release Date: 22/09/2021
👨‍💻 By: @amolamrit

📝Changelog:
• Source Changelogs
• Add livedisplay
• Adjust keyguard margin
• Update build fingerprint
• Update model name & device name
• Disable smart pixels because it was causing issues

ℹ️ Notes:
• Our FOD sensor has some limitations, it does not work well with high intensity night light, animations and different FOD icon colors when it is pressed. So please do not report bugs realated to them. It is advised to use the "stock like" animations and FOD icon colors (Cyan, Green) or else your FOD won't function properly.

🆕 ShapeShift OS 2.8 UNOFFICIAL for OnePlus Nord
📅 Release Date: 23/09/2021
👨‍💻 By: @sneax042 & @alwaysangry

📝Changelog:
• Initial Unofficial Build by a new developer

🆕 Havoc OS 4.9 UNOFFICIAL for OnePlus Nord
📅 Release Date: 26/09/2021
👨‍💻 By: @TheBATVIC

📝Changelog:
• Source Changelogs
• Initial Build

🆕 Stag OS R5.0 Android 11 OFFICIAL for OnePlus Nord
📅 Release Date: 27/09/2021
👨‍💻 By: @vjsPranav

📝Changelog:
• Source Changelogs
• NFC Fixed

🆕 Havoc OS 4.9 Android 11 UNOFFICIAL for OnePlus Nord
📅 Release Date: 28/09/2021
👨‍💻 By: @thebatvic

📝Changelog:
• Improved FOD on lockscreen
• Fixed NFC (Credits to MajorP93) and DT2W also works (Thanks to @AlwaysAngry for perf+ kernel)
• Improved Raise To Wake

🆕 Dot OS 5.2 Android 11 UNOFFICIAL for OnePlus Nord
📅 Release Date: 29/09/2021
👨‍💻 By: @alwaysangry

📝Changelog:
• Implemented FOD Z order
• Ambient Display added
• Adjusted FOD and Charging Info Overlapping
• Add key padding props from stock

ℹ️ Notes:
• Don't use Screen Off FOD. It is disabled, so don't enable as it may cause deep sleep issues. Will fix in next build, Busy AF right now.

Donate:
UPI: raavimanikanta6595@oksbi