simbank raspberry pi pcbboards and chaos

ok so i want a simbank but i dont wnant to spend so much cash on one i found the firmware for it so im thinking that i cnan just buy a 20pc pcb sim adapter from ali express and change the firmware and use the raspberry pi sixfab as the modem ...does anyone have any experiance with these
another question i have about pcb board i see its possible to print them but im assuming printing them and manufacturing are 2 totally different things? and if i have the schematics for a board cnan i just send them to a comppany and have it made that way and just upload firmware to it is that how it works ? i want say ima total noob but when it comes to programming and such im a noob any help is greatly appreciated and im sorry if this isnt the right spot for this its a sim card so i figured it would go under mobile