I believe you cannot stay hands on and technical on _everything_. You might have some specialties you are good at from before becoming a manager, and have constructive input there. The rest, you delegate to other, usually senior members of the team. They will be better suited to do architectural decisions and code reviews than you.
In the end your senior developers will end up better developers and better in technical stuff than you. And that is fine.
In the end your senior developers will end up better developers and better in technical stuff than you. And that is fine.