Or are you worried about clones?
I'd also discourage a patreon- or kickstarter-style offering for a B2B product, because it signals very clearly that you're not playing with the big fish.
As for signaling, one would not have to use those providers if they felt it did not fit their brand, and could roll their own platform. But if signaling that you want to "play with the big fish" is what one wants, most companies hire sales team who go out and play golf with prospects. Having an open source product and using other forms of funding certainly does not preclude doing that. (Though being a small bootstrapped business might make it more difficult).
While charging for use might seem like a good business model, I think an awful lot of potential customers will just never use it because of it. You may be able to find a model where you charge for the front-end page designer or something, but open source everything needed to run the site so that being locked in to a product you have to pay for and can't modify is less of a concern.