@Danny Have you checked your ram? is it low like 4 or 8gb or high like 16 or 32gb? And what Is your OS? And what are your export presets?
This could be a problem of your ram because when you make high length clips with highest resolution or even on lowest resolutions due to longer lengths on low rams many times also in other video editors stucks. Make sure you have high ram to make exporting complete.
And whopping storage doesn’t matter because when I first installed shotcut on my pc I had problems exporting even I had Four 1 TB SSD on my (Storage customized) computer means 4 TB Storage but I realised my ram is low.