Hey there!
I always found that software secrets/credentials to be a pain to manage, and relying on a third party, means they actually own your secrets - and so I made a simple secrets manager named secretsfly ( https://github.com/martinlevesque/secretsfly ).
The main point is to have something as dev/user friendly as a secrets manager such as https://www.doppler.com/ but where you own the master keys and can easily self-host it in few minutes, and something much easier to manage and learn compared to something like Vault hashicorp ( https://www.hashicorp.com/products/vault ) - and so secretsfly is kind of in between.
A demo instance is available here https://secretsfly.fly.dev/ - feel free to test it out and create whatever you want, and let me know if you have any suggestions or idea.
Cheers