In the first attempt everything was printed in pla and a round heat bed was installed. The result was not very robust and I encountered several issues in terms of calibration. So I decided to give in another shot.
Second round
In the second round, everything was printed in PET filament, the entire structure was secured on a wooden bottom plate, the rods were replaced with carbon ones and springs were added. Furthermore, the extruder head was updated with an aluminum base plate and a more suitable fan duct. Printing results were greatly improved and with no need for constant recalibrration of the built plate.