Resurrect old blog

Hi Guys

So ive recently just came across a file which contains a backup of an old blog.

The blog was split into two sections

Root domain was used for my old domaining and didn't really use to pull many visitors in.

Another part of the blog was domain.co.uk/Blog2 and was used by my partner who created quite a large blog which got 20k visitors per month if I remember rightly.

What is the best way to resurrect this blog but move everything from domain.co.uk/Blog2 to the root domain?
Obviously by moving to root ill lose all backlinks to specific pages and there will be problems with internal linking etc?

Any advice appreciated

Side-Hustle

if you 301 redirect the good URLs (the ones with many and / or strong backlinks) to the newly created URLs on the root domain you won't lose anything