iphone in recovery mode can't update and restore

My iPhone stopped working about two weeks ago. It suddenly turned off and when i tried turning it on it would only turn on till the apple logo came out and then it would turn off, it's been on a loop. I put my iPhone into recovery mode.After doing some research i saw that i had to connect it into iTunes and update it and restore it. When i tried updating it, it took longer than 15 minutes and when it takes longer than 15 minutes it automatically turns off and exits recovery mode.(iTunes will download the software for your device. If it takes more than 15 minutes, your device will exit recovery mode and you'll need to repeat steps 2 and 3. - iTunes) so my other last option was to restore it. So i connected my phone back into iTunes to restore it since i couldn't update it. So i tried clicking the option to just restore since i can't update it, but it only gave me the option to "restore and update" not the single option to just restore. So now i'm out of options since i must update it if i have to restore my iPhone but it turns off every single time since an update usually takes an hour but my phone always shuts off while trying to update it since it's been connected for longer than 15 minutes in recovery mood. I don't know what to do anymore. (my phones an iPhone 6)