Does not turn on (been unused 15 months)

I broke my iPhone 8 screen. And now Xmas and time, I changed the LCD but came out black (working on this problem). In the meanwhile. I took my old iPhone 5S for temporary usage. However it will not turn on. It has been on the bookshelf 15 months. I connected with power cable to MacBook and iTunes, restoring. Tha Apple logo shows and a line under it. But after a while, iTunes prompts : “could not be restored. An unknown error occurred 4014. I have tried to restore 3-4 times. I have tried with two MacBooks and they are updated. Also with two cables. Problem remained. All service centers are closed as Xmas. Phoneless. 2 days now. Sharp ideas welcome!