Perhaps look to your marketing folks rather than engineering.

"Purchasing silver sponsership with [org] as a way to grow our brand awareness" is intrinsically understandable to pretty much any businesses manager.

"Giving away money for something we already have", which is what most technical managers will hear regardless of your actual pitch, is completely inexplicable to many.

It does require that sponsership is even possible, and recurring sponsership may be harder than recurring license fees of course, so its not a sure thing, just an option to try.