Does this rom support Dash Charge for the 3T? And how should I flash the rom?
Yes, dash charge works.
Your install procedure looks fine, i used this one:
Install PixelExperience on oneplus3 - PixelExperience Wiki
Also usefull to know for me:
LineageOS is a free, community built, aftermarket firmware distribution of Android 10, which is designed to increase performance and reliability over stock Android for your device. #include /* * Your warranty is now void...