What shall I do with the saved church - taxes?
1. Possibility: I distribute the saved church - taxes for social purposesses

Ny advice: No, that would be a wrong thougt. If you want to superseed the church taxes by another tax or fee, you will justify the church - taxes in a moralic way. That regards also to other gift given in a volunteer way.
Please distribute no more or less money for social purposesses after you had suceded from church. Otherwise the church - tax payers would be advantaged to make their use in an unjustified way from social institutions, because they have paid less money for it.

2. Possibility: I buy luxury - goods for my saved church - taxes
My advice: This opinion sound to be egoistic, but it doesn´t so. At least the church does nothing else with the money we ´d to pay. Because the church has never got a bad conscience, we have not got at all.
Besides them private persons have to pay high taxes for luxury goods to secure the welfare of people - in contrast to the church. Don´t accept feelings of guilty. You have done a better service for people by buying luxury goods than the church which spents only 8 % for social purposesses.
3. Possibilty: I save the saved church - taxes for times of misery or old age insurance

My advice: Surtely that would be the best solution! Thereby you will help yourself and other people. Even during times of misery you will not depend from the relief office, and your own care about yourself will ever be the best security.

You ´ve worked very hard for the money you paid to the church till now. It is your money! And so it is your decission what to do with it.
I can and want to give argument only.