Protect "Riesterrente"-retirement account from downside of liquidation

The amount of protection that a put provides depends on how effective you want it to be, somewhat like collision insurance on a car (U.S. centric). The larger the deductible, the lower the cost of the insurance.

Premium decay is non linear so the longer the duration of the put, the cheaper the cost is per day.

An at-the-money put for Dec '21 (the furthest expiration for MSCI) costs about 14+ pct based on a price of $395 for the MSCI which is 16+ pct per year. That's an awful lot of drag on a portfolio before it begin to profit.

Insuring 20% OTM for Dec '21 would costs about 6 pct (almost 7% annualized) but the deductible would be 20%. Still expensive.

A less expensive way might be if you could find a more liquid MSCI ETF as a substitute and it offers less expensive options.

I have a mildly similar situation. I have an income annuity based on the S&P500 that pays me about 10% a year if the index is up one penny over the previous anniversary date. It comes with 10% of downside protection (each year, I don't lose a penny if it drops up to 10%).

Since this is what I consider to be 'safe' money, every year I buy one year or more 10% wide vertical spreads that are 10% OTM. That protects me for another 10% of drop (less the cost of this protection). In non volatile times this costs me about 1.5% of principal. During the year I am usually able to make a few adjustments that lowers the total cost and eventually I cover the short puts when they aren't worth much, ending up with only long put protection. The net result is about 1/2 to 1% out of pocket so my additional protection is 9 to 9-1/2 pct more than the initial 10%. Due to the non linear nature of premium decay, I roll the long puts out to a later expiration before the last few months when time decay speeds up loss of premium.

Last year I was incredibly lucky. When the market crashed 35% in March, I had long SPY puts worth maybe 12 cents expiring in a few weeks and I sold them from roughly $15 to $20 or so, avoiding most of that 35% drop as well as increasing my so called income.

The point of this is to share a real life example of what you are considering and hopefully, it gives you some insight into other possibilities.