Yep, replacing the motherboard is accurate. You can replace it with the guide below and I have also provided you with a motherboard replacement part.
[guide|106275]
https://www.aliexpress.com/store/product/JUN-FUN-Full-Working-Unlocked-For-Nokia-Lumia-930-2GB-32GB-LTE-WCDMA-4G-Motherboard-Mainboard/https://www.aliexpress.com/item/JUN-FUN-Full-Working-Unlocked-For-Nokia-Lumia-930-2GB-32GB-LTE-WCDMA-4G-Motherboard-Mainboard/32857656895.html