You can store encrypted values in your ASP.NET Core configuration file and seamlessly decrypt the values as you retrieve them. But there are, at least, two issues that you'll need to address.

Take advantage of connection resiliency in EF Core to detect errors and retry commands and enable your ASP.NET Core application to overcome transient faults.

Report Designer - How to read connection strings from different configuration sources in an ASP.NET Core application In .NET Core applications, the default connection string provider implementation ...

ASP.Net Core + SQLite "Could not find connection string" #1451 Open DjeeBay opened on Jun 20, 2019 ...

Take advantage of trace listeners in ASP.NET Core 6 to add performance and debugging instrumentation to your applications with ease.