Try to find an typical consumer inkjet printer on AliExpress, you won't find any, or if you do, it will be someone reselling the usual brands like HP or Canon. You will find label printers, industrial printers, 3D printers, thermal printers, and all sorts of weird stuff, but none of them able to put ink on a stack of A4 paper.

If the Chinese, who are known for being able to make knockoffs of everything are not able to make inkjet printers, this should tell you how hard it is.

It addition to the print head, reliable paper transport is also really hard. That problem is often sidestepped by using a paper roll or by printing one sheet at a time, as it is the case for the Openprinter.