Is it permissible to take interest from a usurious bank with the intention of spending all of it on a charity that supports Muslim causes, or is it better to leave the money in a current account without interest?

A good intention does not justify a forbidden means. Therefore, it is not permissible to deposit money in an account to obtain usurious interest and then donate it, as this involves acknowledging usury and engaging in it without necessity. However, it is permissible to keep money in a current account in a usurious bank as needed.