If this is just about providing monetary support for the project then just do what everyone else is doing: sell support or pre-built copy&past examples. If the plugins are nothing special and can be replaced by a one-liner I would be even more pissed after paying 300$ for them.
Either these guys are really, really bad at communication, or this smells really fishy. If anything, this blog post makes me trust them even less that they won't enshittify Datastart by moving more stuff to Pro and having the FLOSS version be the ghetto version.