Here’s a quick video on squaring the X-Z section of the Prusa Mini to the Y axis. In particular the overhanging arm to the heated bed. For some reason this aspect of the assembly process is completely ignored in the manual – and while the printer makes aesthetically pleasing prints, and the first layer calibration and bed mesh levelling is great, it is difficult to get accurately square prints without performing these steps. If I had known this I’d have probably bought the MK3S+ kit.

My Top 3D Printers: https://miscpro.com/top3dprinters/

My calibration prints available here: https://www.thingiverse.com/thing:4140075