NUC 14th gen with i3 is around 400 EUR with VAT, with no RAM or storage. For the other 250 EUR, surely you can get more RAM than 16 GB and more storage than 256 GB.
I use a NUC as a daily driver. The problem with NUCs is that cooling is suboptimal, the fan is small and thus noisy. It can be fixed with a third-party case, but that's at least €60-100 more for a much slower machine. Plus, you may void the guarantee by transplanting the motherboard.
It’s a shame that ASUS cancelled the NUC Extreme line. I know it’s quite a bit bigger than other NUCs. But the 13 Extreme had expandability, good cooling, and fast CPU options.
4 cores instead of 10 cores, 69W TDP instead of 22W, UHD Graphics 730 versus Apple's 10 core GPU (0.5 TFLOPs vs about 4.3), 23% worse single core performance, 45% worse multicore, and much louder cooling.
Apple is certainly out of their mind on storage. But on a desktop it’s trivial to plug-in an external disc that you can buy at an absolutely reasonable price instead of the insane Apple one.
$200 bucks for 8GB RAM extra is not fair ($200 to go to 24GB, another $200 for 32GB). 64GB DDR5 kits can be had for less than $200.
And while you can plug in storage, I think it does kind of ruin the appeal of having such a small device by having a bunch of spaghetti cables. And if the boot drive goes it's not easily replaceable and makes the machine a brick until it is.