Should I try to repair the edge on this blade, or is it better left for display? No attachment to it, but wouldn’t mind shaving with it one day. But also, no willing to sink a bunch of money into it either if it’s not worth doing.
Hard to know what 'worth doing' entails. Were it mine I would definitely try to save it, but I have the hones and experience to do it without spending anything but time doing something I enjoy doing anyway. You didn't say what brand it is, but the design on the tang reminds me of a lot of generic hardware store razors that I have seen. As such it will never be worth much money, but my experience with similar razors has been that they make fine shavers.
It looks like the integrity of the steel has been compromised from rust or oxidation at some point then restored.
The steel may not be able to support itself. Hard to say without actually having it in the hands.
looks like a fair bit of metal will have to be removed to get past that crumbly bit, if you have low grit stones and a bit of time it should be salvageable