Exactly - that would be amazing. Like a backup power solution (that's affordable and safe) that's compatible with any pump. Surely it can't be that difficult - arrggghh.
You should be able to buy any pump - it should not come with a controller (which should reduce the price of the pump). You should just be able to connect it into any Controller - like Apex or eKoral. There should be a variety of of batteries that plug into that controller. When the power goes out your return pump should just keep going (on power saving mode).
I see so much of the people in this hobby had awesome DIY skillz but I wish I'd have know it was so important. If someone like eKoral does what you are talking about Mitch I think it will rapidly open up this hobby to a lot more people and that'd be better for everyone.
That is the idea to allow more innovation and collaboration. Existing platforms I feel personally could implement an interface into their existing controller offerings that would communicate with other device like a bridge between their platform and the "industry standard" and do whatever translations within their codebase to the standard for functionality to work. At that point, in your example a controller for the pump would be completely an optional purchase (similar to how you can buy the Gyre pump without the controller).