If you do it perfectly then you won't face any issue, there are few risks, your phone might brick or go into boot loop, it only happens if the connection to the laptop/PC gets interrupted while sideloading, 1-2% chance it will still happen if it goes...
Downloaded the update from a forum, just search in youtube, there is guy showing how to sideload, but there is always a risk of bricking the phone if you don't do it properly
