I’m on my phone at university so you’re lucky I can’t get my BTC address to beg, lol.
On a serious note, I have been thinking about the same thing recently as well as the holidays are coming up. If I had a million dollars, would it be a curse? Along with this, ever since I started walking this spiritual path I’d wonder if I’d get more pleasure from spending on those in need or less wealthier. Even around Christmas this year the only thing I ask of my parents is a cheap $50 tablet and yet I’m getting over $250 worth of presents for my family. So rest assured, I believe this is a somewhat common thought that us Christians have from time to time, as you said we are called to be charitable and let no material possessions stand in the way to Him.
What I would suggest to you in regards to getting the most out of being charitable to others is to offer anything other than money to them. A homeless man may spend $20 on alcohol and drugs, but if you walk into McDonalds and buy a few hamburgers and then give him that, there’s nothing to aid his ulterior motives and it feeds him for the night and it’ll have you living in their minds rent-free. To answer your question, there is no definitive guarantee God will grant you greater things if you are charitable, especially if you are only giving because you seek gratification or good karma, he may or may not. What I can say is that being more charitable and voluntarily stripping away your possessions may bring you closer to him as it opens a door to the idea that wealth and possession is such s temporary thing, and frees that potential obstacle in your relationship with Him.
To add onto this, you can use your charity to also spread the gospel in a similar way by buying bulk packages of pamphlets and apologetics to use in evangelizing people. I myself am tempted to save up for a few cases of apologetics and Bibles after the holidays. There are thousands of ways to get out there and spread the Word, anything from buying a hundred Bibles and handing them out on street corners or signing up for and paying for missionary trips to India or Africa, every little bit helps and I’m sure you wouldn’t feel empty as you help people start their journeys to salvation.
Overall, if you don’t need it as you say I suggest you put aside what you need for the future and with the rest, don’t be afraid to help others should they need it and are reasonable, and using it to spread the Gospel is absolutely a good use of it. Also if this helped you significantly, I wouldn’t mind you helping a bit with the evangelizing expenses I mentioned.
I hope this helps you in some way, anon. God bless you.