I'm in the process of buying and evaluating mini-PCs to replace my Pi 4. Right now, I'm trying out the Minix Z100-0dB, which is a fanless N100 system. It's great—around 6W idle, with zero coil whine or any other noise.
I also got a Geekom A5 with an AMD Ryzen 7430U, which is a 15W TDP CPU that's about 3x faster than the N100. It's crazy, because even though it has a fan, it idles at just 4W! (That's with an additional 2.5" SSD connected via SATA, plus the standard 2 x 8GB DDR4 and 512GB NVMe that came in the box.) I mean, it scores around 15,000 on CPU Benchmark, compared to the N100's 5,000. And the Pi is way below both of them.