This happend to me on J3 2017, I left it for more than 48 hours but nothing. Then phone batery ran out, so phone reseted and firmware was deleted. I needed to download new firmware with Odin to phone from https://www.sammobile.com/firmwares/. It took me 8 hours too download it, becaose that site has Premium with normal download speed, but you need to pay for it.
Put file in Odin and start downloading.
That process will fail hidden(it should fail) and you need to make a last step manulay. Link for official Sammobile tutorial :https://www.sammobile.com/forum/threads/35929-SOLVED-firmware-flashing-FAIL-after-hidden-img
I do not know if is this going to help you, but you can reset phone with this method to a state before you start this. And if you do everything good you wont loose your data.
And for PIN reset you can just make hard reset :Volume Up + Home + Power button for a couple of seconds and navigate with Volume button to hard reset. It will wipe all of your data to factory settings(if you have Samsung Acc. backup everything will be safe), including PIN code, but you need to input your gmail pasword (if you have gmail on phone) to unlock it,or phone will be locked.