[Huawei Mate 20 Pro Guides, News, & Discussion] ilos:
Found it (China version LYA-LGRP1-CHN 10.0.0.166 don't flash it on LGRP2)

http://update.dbankcdn.com/TDS/data/files/p3/s15/G4344/g1755/v320976/f1/full/update_full_base.zip

Not sure that emuiflasher work with it

This is an EMUI 10.0 open beta test (OBT) informal commercial version provided for you to experience new software features in advance, thus giving us feedback for further software improvement. Note that the OBT version is still in the development phase, and problems or defects may exist. Back up your important data in advance.
Note:
1. Before installing this update, delete or remove large files from Files > Internal storage > Android > obb to prevent the updating failing due to insufficient storage.
Problems that have already been identified are currently being rectified. The major ones are as follows:
1. The screen sometimes freezes when viewing recent tasks.
2. Non-Huawei nano memory cards may not work properly.
User interface: intricate and breathtaking
· Magazine Design
AI-powered Magazine unlock screen for a wholly reimagined aesthetic page design and riveting text descriptions
· Morandi Color
Understated gray tones make for a gentler and more comfortable display
· Animations
Dynamic, naturally-based animations for page transitions, app launches, and other scenarios
· Member Center
Adds the Member Center desktop icon, for easier access to Member Center and related services
Performance: stable and smooth
· Ark Compiler
Adds support for over 35 mainstream apps, and also improves app speed and operating smoothness.
· GPU Turbo
Improves the smoothness and stability of the system when playing games.
· Phone Clone
Improves the connection and cloning speed.
Security: more secure data and privacy
· Formally verified microkernel
Uses Huawei's own self-developed microkernel design, certified as the most secure OS kernel for commercial use.
· Distributed technology
Improves security when connecting to other Huawei devices, as well as when transferring files between and storing data on other Huawei devices.
· Privacy protection
Supports app sandboxing capabilities for standardized app permission management and more secure data and privacy protection.
Smart office: collaborative and efficient
· Multi-screen Collaboration
Allows you to drag and drop photos, videos, and files between your phone and Huawei laptop with a single tap, and also to control your phone with the keyboard and mouse.
MEETime: HD video calls
· High image and voice quality
Supports HD voice and video calls between your phone, smart TV, and speaker, even in dark environments.
· Take calls on your preferred device
Allows you to take calls on the device that suits you, whether that be your phone, smart TV, or speaker.
· More fun
Supports sending voice messages to your smart TV, as well as adjusting beautification with a single touch during video calls.
Smart assistance: more responsive and intelligent
· HiVoice
Interact with Xiaoyi to enjoy continous assistance with a single wakeup
· AI Lens and HiTouch
Automatically displays JD's shopping screen after scanning a product or touching a product image with two fingers.
· Scrolling translation
Supports translating onscreen text in real time while scrolling down a page.
Media and entertainment: more fun
· Connecting to mobile gimbals via Bluetooth
Supports using the DJI Osmo Mobile 3 to take photos and record videos with the camera.
· AppAssistant dropzone
Adds a dropzone for AppAssistant, allowing you to quickly access services such as game acceleration and do-not-disturb.
Update notes:
1. This update will not erase your personal data, but we recommend that you back up any important data before updating.
2. Some third-party apps that are not compatible with Android 10 may function incorrectly after the update. It is recommended that you update these apps to their latest versions in HiApp.
3. This system version can be rolled back to the official version of EMUI 9.1 using HiSuite. Rolling back the system version will erase your personal data. Please back up your data in advance.
4. If you encounter any problems during the update, please visit HiCare, Huawei Club, or call the official VIP service hotline on 400-930-9300 for assistance.
5. Your home screen layout may be rearranged slightly.
6. For more features, visit Tips.