Now @YouTube rolled out Incognito mode to all its Android users. If you didn't get it yet check for an update on play store. This is what many users have been waiting for and finally YouTube rolled it out. Please also release the night mode update for Android ASAP. @YouTubeIndia.
Thank you, @TeamYouTube. I updated it two weeks back. By the way, thanks for the response. I am exhilarated to use dark theme.