You'll regret more all the things you didn't do than the ones you did.
You'll have more regret for the things you should have done than the things you already have done.
ご質問どうもありがとうございます。
様々な表現があると思いますが、いくつか自然な表現を紹介します。
- You'll regret more all the things you didn't do than the ones you did.
- You'll have more regret in life for the things you should have done than the things you already have.
お好みに合わせて使い分けてみてください。
ご参考にしていただければ幸いです。
ドイツ 
