How to fix baseband error iPhone 6 but no original baseband IC

hi there

i have some problem with my current iphone 6

i already bought secondhand iphone 6 with baseband issue (no imei shown) in activation mode so it can’t be activated because no imei

now i already taken apart my phone and it has no Baseband IC (some of the solder pin are missing)

i already ask some phone repair shop that they can’t do repair because of missing baseband IC

but i’m just curious, can it be repaired ? for example buy another baseband IC and solder it to the mainboard ?

also if it can be done, are there required special tool to re-program baseband IC ?

thankyou for your answer