There is an opinion in the Mishna (R Shimon, aficr we don't pasken that way), that even if someone has money in the bank, yet does not use it, there is a mitzva to give him tzedaka.
You might not understand, and I agree it's infuriating to work yourself to the bone to fund somebody living a higher and easier lifestyle than yourself, but sometimes that's what G-d wants from you. Here's a way to do tzedaka without the immediate return of satisfaction.
Ma'aser is a very abstract chiyuv and I'm sure most rabbis would be very lenient about what you can use it for. The main guidance we have in chazal about prioritizing is Anii Eirecha, if someone in your family has a need, or in your neighborhood, etc.