I'm not a fan of SealedSecrets or managing secrets in-code at all because of this scenario: Secret rotation requires pushing updated code which may take too much time in a compromised situation. Ie, I don't want to hinder secret rotation with CI tests and merge approvals when there's an active incident triage - I want to kill the pwned secret with fire and get a fresh secret in there ASAP.
I've gotten better results by treating secrets as state instead of infrastructure... Like, by coupling your pod to a secret vending service like Vault or Secrets Manager, you can remove potential for programmers to introduce anti-patterns that weaken our posture.
The benefit is that we can keep things encrypted, auto-rotate things behind the scenes, remove the chance of developers to have even an encrypted copy of secrets, and we can get better turn-around on IRs when secrets inevitably get leaked. And, you can still write out the secret as IaC.
To mitigate the potential for single-points of failure when the secrets service goes down is to allow for secret caching client side. Vault and AWS Secrets Manager, which are the only services I can vouch for, both have client-side caching capabilities.
Take that with a grain of salt. I admit, I'm opinionated