Getting the emulator to run is like hit or miss. It will take you time to get it working as you wish.
If you insist, there are several things you may try:
1. Delete the image and create again from AVD Manager. Try different Platform - 24, 28, 30 ? (google_apis_playstore and default, x86 and x86_64).
2. Run using Cmd
C:\AndroidSdk\tools>emulator -avd 10in_Tablet_Platform_28_default
3. Download all Recommended items from SDK Manager
4. Power off and on a few times. Try wait a bit longer as it may take some time to boot up.
5. Close some programs and make sure you have enough RAM
Since you are able to run 6in emulator, I assume it is not related to Intel CPU, Virtualization, Hyper-V, HAXM issue.
Lastly, if you want to create screenshot, you can take it from your real device and copy the image using File Explorer by enabling "FTP Server" in B4A Bridge.