From experience, the range is €50 to €500 per year. Many plans scale the bonus by the number of criteria you meet. If you only prove the check-up, you receive the base amount. If you meet all components, you receive the maximum. Payment is usually made in the following year, after the insurer has checked the proof you submitted.
If you stay with all components consistently over the years, you can collect a four-digit amount over a decade, with documented prevention as a side effect. To be honest about its place, measured against an annual premium of several thousand euros, the bonus is a bonus, not a premium lever. The big levers for the premium are the choice of plan and the deductible.