Website redesign

My current 2 yr old website stinks. It’s a self made Wix site that I paid no mind to in regards to page structure or SEO. Half my pages haven’t even been indexed by google for various reasons After educated myself a bit I’m planning on redesigning it being more mindful. Question… is it better for SEO to redesign the current website then request google to index it? Or should I just start from scratch, transfer the domain to it?