I would recommend a new lens too.The lens makes a huge impact on image quality much more than body changes in my opinion. I am still on my beat up A7. Recently got the 85mm f1.8 and the boost in image quality from my 28mm and adapted lenses A-mount lenses was very refreshing. However I am 2 generations behind the A7III so I will be upgrading body as once prices normalize and stocks are readily available.
Image stabilization, battery life, faster auto focus, 4k, low light performance compared to the 1st gen A7 makes it worth it for me. So decide based on what you really want.