Honestly, you should charge actual money for this.
Not a bad idea at all, plus the templates you already have are pretty neat. I could see applications w.r.t. professional development or even marketing to product people with the purpose of simplifying product roadmaps (and sharing with C-levels, etc.).
You have something here, screw donations. Free users suck anyway; my free project[1] has ~1500 MAU and I kind of want to stop working on it because the entitlement is unreal.
That's what I'm intending on doing next! I'm trying to find distribution channels to reach out first and to validate some ideas I have in mind. Would you like to hop on a quick call to brainstorm stuff?