To estimate the FFO / Net debt ratio for 2022, let's break it down step-by-step.

**1. Calculate Funds From Operations (FFO)**

FFO is typically calculated as EBITDA, minus net interest expense, minus current taxes, and adjusted for other items. Since we don't have a formal FFO statement, a common proxy is:  
- Start with **EBITDA** for 2022: 3,160,679,000 EUR  
- Subtract **Interest Expense**: 101,703,000 EUR  
- Add **Revenue from Interest**: 40,132,000 EUR  
- Subtract **Income Tax Expense (Continuing Operations)**: 583,352,000 EUR  

So,  
FFO = 3,160,679,000 - 101,703,000 + 40,132,000 - 583,352,000 = **2,515,756,000 EUR**

**2. Calculate Net Debt**

Net Debt = Total Financial Liabilities (current + non-current) - Cash and Cash Equivalents.

From the balance sheet at **2023-01-01** (end of 2022):
- Non-current Financial Liabilities: 2,844,559,000 EUR  
- Current Financial Liabilities: 1,109,297,000 EUR  
- Cash and Cash Equivalents: 409,252,000 EUR  

Net Debt = 2,844,559,000 + 1,109,297,000 - 409,252,000 = **3,544,604,000 EUR**

**3. Calculate the Ratio**

FFO / Net Debt = 2,515,756,000 / 3,544,604,000 ≈ **0.7098**

Final answer:
<answer>0.71</answer>