https://unchained.com/bitcoin-ira

Unchained let's you hold your own keys to real bitcoin under a Roth IRA legal structure. This means when you withdraw from the Roth after retirement age you pay 0% tax. This could save you a lot of money in taxes considering bitcoin's upside potential.

This is great if you already have an existing Roth but want to short the fiat bubble. You can convert your existing Roth to this.

The tax advantage is compelling but the wait is long for retirement age. You can always withdraw early if you are willing to pay taxes on it but I would get enough non-Roth BTC to be comfortable until then too.