Yeah the APU2 handles gigabit no problem and the CPU is plenty fast. They have really nice intel NICs, see https://pcengines.ch/apu2.htm. As you say, ships with coreboot.

I've been using APU2's for years (and before that APU and ALIX). The ALIX couldn't really saturate gigabit, but iirc even the APU could. Highly recommended.