One takeaway from this discussion is any sort of customer-facing service offering (including a beta) should be decoupled from LibreTime development. Using Open Collective as a conduit, developers could build and maintain custom features and specific integrations (i.e. Drupal, WordPress), provide security updates, mentor and train users members via a partner or organizations collective.
For example, if Fourth Estate had a collective, it could create a campaign for each custom instance of LibreTime. Developers could invoice against the collective and/or a % of funds could be transferred to the LibreTime collective as a way to fund ongoing development.
A service provider/partner could use Open Collective to help sustain the OSS project(s) and contributors in a similar fashion.
The LibreTime team is still sorting out a process for using Open Collective and other tools to sustain the project. Accommodating the needs of partners and supporters in this discussion should certainly help.