The Vivobook 16 uses soldered DDR5-5600 (worst of both world, slow and non upgradeable) not LPDDR5x-8000 that should explain the difference. Power limit wise the chassis is actually quite generous.
It's not a great first start for the midrange Radeon 860M when it can't even match most older Radeon 760M laptops already in the market. Casual gamers may want to consider the Arc 140V or double-down on higher-end Radeon 880M or 890M options.