Z3 Bootloop

[Amromnia913]

My cousin has an xperia z3 dual d6633 we wanted to root it so what we did was :
1- we unlocked the bootloader using sony's official guide that was a success
2-we flashed twrp using

fastboot flash recovery TWRP.img

That appeared to be a success but we failed to boot to recovery i tried everything to boot to recovery from pressing power buttons with each volume buttons or both to even using

adb reboot recovery

and even that didnt work it always booted to android
3- when that didnt work one guide on the internet said to boot directly from the twrp image i had on the pc using

fastboot boot twrp.img

and thats where things went south it still booted into android but this time it was stuck in a bootloop it would boot into the screen thats right after the sony logo (the one that looks like the ps4 booting screen) and it would keep doing the animation non-stopping
4-we tried using xperia companion to fix it but it always said bootloader was unlocked
5-we tried relocking the bootloader using both

fastboot oem lock

and

fastboot -i 0x0fce oem lock 0x<unlock key>

mimicking the unlock bootloader command from sony's website but the lock bootloader keeps going on forever nothing happening until we take out the usb cable then it says failed
now i have two questions
1-can this be a hardware problem? Basically can the steps i made damage hardware?
2- is there a way to either relock the bootloader to fix it using companion app or fix it using any other program at all?
Thank you for answering