Scaling Bitcoin is the only long term solution for sovereign digital identity beyond the features that Pkarr already delivered on... If you want sovereign digital identity for organisations, or families, or individuals that don't want to opt in extreme security setup from day one, or if you are concerned about quantum for some reason... You need a total ordering of events, and that can't be done without a Blockchain and sharding through L2s...
If you can secure bitcoins with covenants, you can secure identities too. Programmable money is programmable data so it can be programmable phone book.