Reviving an old topic - I wondering if this has been considered as a Cloudron development.
Radius would be complimentary to OIDC and LDAP functionalities of Cloudron and fill the gap in a number of (enterprise) situation
I am not sure how complex it would be to integrate an open source product such as freeradius, already well established, with the Cloudron user directory.
But if not too complex, I'd wager the trade off of integrating this as Cloudron "core" (as opposed to an app) vs the benefit it provides would make Cloudron's positioning fairly unique and thus interesting/relevant.
I would also enjoy a freeradius implementation as an app as suggested here by @andreasdueren, but unless mistaken, freeradius does not have any baked in GUI, so it would ultimately add in complexity in places which could spare some.