It's a very nice and worthy idea. Please kindly note that there already are a few of these platforms (but maybe there is room for more - perhaps if you add something unique to the model).
Examples:
https://chuffed.org/
https://www.thebalancesmb.com/giving-to-charity-online-2501931
https://www.gofundme.com/
https://doublethedonation.com/tips/crowdfunding-platforms-for-nonprofits/
Good luck
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