Checkout https://www.getgrist.com https://www.getgrist.com. You can start with their SaaS offering (they have a nonprofit rate) and if it's what you need but th

Checkout https://www.getgrist.com https://www.getgrist.com. You can start with their SaaS offering (they have a nonprofit rate) and if it's what you need but the cost is still prohibitive, you can run the open source version as self-hosted. (Full disclosure, I used to work on Grist, and now I use it at work for any critical data I find living in a spreadsheet.)