Help with flashing stock ROM on Nokia 3.1 (Mediatek MT6750)
I had the same problem as you, after looking in a lot of forums I managed to solve it, I hope it helps you.
My phone was no longer able to access the recovery, nor fastboot. After trying lots of Rom and various methods, I will explain to you which one I recovered the mobile, that is, losing the Imei, but for that there are many valid solutions.
Enter the page https://www.needrom.com/download/nokia-3-1/
You have to create a premium account to download, but they are 3USD for 1 month, download the Rom and the flashtool from that link, when it flashes put it in Firmware Upgrade mode and uncheck the preloader, sutinfo, systeminfo and cda boxes.
It worked perfectly for me and after that he let me update via OTA to Android 10.
Greetings.