It would be great if I could have a retirement saving in crypto like Bitcoin, but I would prefer to keep it myself, not in a government-appointed institution because I feel safer seeing our savings in my personal wallet so I can keep monitoring that it's still safe and by remaining in our personal wallet we can determine for ourselves whether to keep it or exchange it for other types of investments that can also provide passive income when we retire.
This is a very important point you raised here. Nobody would actually be in their right mind if they create a retirement plan with Bitcoin and deposit those funds into a government controlled centralized institution. That is really against the whole point of Bitcoin.
If these retirement plans actually ever exist, there should be some coding mechanism that you can prove with to the government that you can't touch the wallet up to a certain point in time, or if you do any tax benefits or top ups granted from the government will be deducted again calculated according to a certain predefined table.
I don't know exactly what the perfect solution could look like, but depositing Bitcoin into a government controlled custodial wallet for decades would make me nervous.