It's better now, been annoyed like you but the Rpi5 comes in a 16gb variant and has a PCI-E port that can be extended to 5x SATA or 2x M2. It's not blazing but probably an improvement over my old Celeron J1800 with 8gb of ram.

The Intel N100,etc series of machines seems popular with builders even if the RAM restrictions drives me nuts.

I think the major issue seems to be cases actually, there's tons of small cheap AMD machines from manufacturers like BeeLink that trounce most NUC setups for performance, but like the NUC's as soon as there's disc enclosures the price shoots away.