Could you be more specific what exactly you are talking about? This thread is for the WiiM Amp Ultra, which sells for around 600 EUR. Thanks to dual TI TPA3255 chips and PFFB it can drive speakers down to 2 ohms, no problem. The power into 4 ohms is exactly twice the power into 8 ohms. Below 4 ohmy, the amp is still stable, but current limited by its PSU, so the power does not double compared to 4 ohms.
Discussing the power (or current) demand is always most meaningful when taking the complex speaker impedance, the speaker efficiency, the listening distance, the room size and the desired average listening level into account. For those dedicated to desktop listening a hand full of watts is more than enough to reach live orchestral levels with moste any speaker.