GoKawiilAnalogue 3D's 4K label refers to output, not native game resolution
Analogue's FPGA-based N64 remake, the Analogue 3D, outputs video at up to 3,840 x 2,160 pixels, but the original games it plays were rendered natively at far lower resolutions, typically around 320 x 240 and occasionally up to 640 x 480. The console upscales and cleans up that old output—removing blur, distance fog, and choppy frame rates—rather than generating new high-resolution textures or geometry.