Has anyone brainstormed about how Bitcoin can be used for a general population election while maintaining decentralization and anonymity?

Is it possible? It must be. I don't know enough details about the technicals of BTC or Lightning to mentally come up with a model, but I keep getting the nagging thought that this can be done somehow, and it would be a pretty elegant solution. Maybe it's from the belief that "Bitcoin fixes this", lol.

Are there any podcast episodes or the like that discuss how an election can be implemented on the Bitcoin network?

One problem is that this relies on the assumption that every voter needs a smartphone of some kind. Some people who do want to vote just don't have one. I would imagine that this is less of a problem as time goes on.

How would one register to vote? I believe there would still need to be a voter roll list somewhere because only citizens of voting age can vote. That one requirement requires a central list be kept somewhere just like currently. Besides this, perhaps there could be a wallet address that is known to be the "issuing" wallet for a certain geographic region. When the citizen presents proof of eligibility to vote either online or in person, this issuing wallet opens an account of a small amount with the voter, like a Lightning channel. Is it possible to send information or a proxy for information in Lightning transactions? Like sending 1 Satoshi to the issuing wallet means vote for Candidate A while sending 2 Satoshis means a vote for Candidate B. The way the LN works, there wouldn't need to be a separate channel opened between every voter and the issuing wallet.

This is just a preliminary idea being thrown out there. A voting system might even be a layer 3 solution built on top of Lightning. This may all be moot with the issuance of Central Bank Digital Currencies too.