sporkle-feet

Not what I could call 'open source'.

Basic features (e.g. 'XML and JSON export') require a subscription to the 'premium' or 'enterprise' plans, even when self-hosting.

grepfru_it

Have a looksie at BudiBase[0], another open source low-code platform. I believe SSO is still functional in the open source version, but roles do not exist.

[0] https://budibase.com/

foxbee

For reference, here is the github link for Budibase: https://github.com/Budibase/budibase