I helped pentest a blockchain voting app with some people at Defcon 2023. This app was designed to be highly secure, transparent, and safe. It would ensure free, fair, and transparent elections anywhere that implemented it. Your vote would be signed by a FIDO2 key you possess (these would, of course, be distributed with your voting registration confirmations), anonymously to the public but signed by your local election board/gov and not giving them more info than they already get. This app was battle tested and hardened at defcon.
Of course, after shopping it around, no election boards etc were interested in it, because, as we know, free and fair elections are not what goes on in a majority of the world including the US of A.