It's not about HOW MUCH it increases over the years. It's about the fact THAT it increases. And my question was related to how you deal with it.
But it doesn't increase to that extent, that's the problem. Then just look at how the REAL WAGE has behaved over the last 20 years. You base your assumptions on IG Metall salary increases but conveniently ignore inflation. At the same time, you might also want to have children, causing a salary (at least partially) to drop, and so on. You already consider an insanely high rate compared to your salary as feasible today.
If you're interested in knowing how your salary will develop over the next 10 years, then take your target pay grade (which surely hasn't been reached yet) and add a 10-15% performance bonus and calculate what salary you would have TODAY with that. Leave out salary increases through IG Metall, Christmas, night and vacation bonuses, bonuses, etc.!!! This is the salary you can realistically achieve. If you ever become a department head, be happy about the additional money, but don't count on it today when financing your home.
Alternatively, I can recommend you to have 152 children. With only a 5% increase in child benefit per year, in 25 years you'd get an astonishing 100,000€ per month in child benefits, uh salary. Your annual salary would thus be well over 1 million euros and Angie and Gauck would cheer and praise you...
Sorry, that had to be said. I understand where you're coming from, but I think you're getting carried away. First, work and save equity. Building a house costs more than you think and you’re obviously not content with a run-of-the-mill house either. If you want to invest, buy a 3-4 room flat in a good location and repay with a 30-year fixed interest period. Your money is invested and you can live there for 10 years and save more money... You can sell or rent the flat anytime later and you'll see where your salary will go.