Regarding the difference between Minisopuru's two Mac Mini M4 Dock models, MINI4PRO and MINI218BPRO

They differ in the number and specifications of ports. And they can be placed in different ways for Mac Mini M4

Model: MINI4PRO 

USB A 2.0 x3 
HDMI port 
SD/TF card slot 
3.5mm headphone jack 
SSD slot 
Put Mac Mini horizontally 

Model: MINI218BPRO 

USB A 2.0 x2 
USB A 3.0 x1 
USB C 3.0 x1 
SD/TF card slot 
3.5mm headphone jack 
SSD slot 
Put Mac Mini vertically