It is great that if you dont have touchscreen you can map keys to certain positions on the screen, so you can move with WASD and use other keys for spells or even navigating the menus.
EDIT: I finally managed to find a screen recorder app that could record in Remix OS at decent quality.
Try DQ on SSD on pc. The smartphones already have solid state storage and DQ runs on that normally. I think lag is probably due to hard drive, ram, processor, GPU etc.
Or it could be an issue with emulator. Bluestacks emulates on an old android device so you’d expect lower performance. If I emulated with any android device like the latest devices, then the issues are lesser.