Vector.im vs Riot.im vs Modular.im ? The FAQ of modular.im asks you to accept a TOS from riot.im . The website demo is on riot.im, but the hosted product is modular.im .
And when you write in to modular.im support, you get a reply from an @matrix.org person. Jobs are applied for on vector.im ...however riot.im twitter page says "formerly vector.im". Modular.im (your hosted slack alternative) page has NO feature list. People are expected to go to riot.im to understand features and play with the demo. In fact your hosted product modular.im has no links to even download the mobile/desktop clients.
People get surprised when I tell them about riot/matrix having a hosted slack alternative that is significantly cheaper and is open-source+E2E. I believe one of the reasons is that have 4 websites rather than one.
Not sure why this situation exists. It doesn't help when making a case for it in the community or company. Gitlab does this well. Please fix.
I don't think you should be uncomfortable with the idea of mixing your open-source products with closed source code (for e.g. modular.im migration tools are closed source) - confusion is the bigger problem.
You made the right choice in focusing on Synapse and letting Dendrite stall. You can build one reference implementation well and let others do as they please. You should do the same on the desktop client.