Is there an alternative HttpClient handler for .NET Framework 4.5 that does not depend on Windows for HTTPS?

I have a legacy project running on .NET Framework 4.5, and we recently encountered issues because HttpClient relies on Windows for HTTPS connections.

Is there an alternative HttpMessageHandler that does not depend on Windows?

I couldn't find any solution using libraries like Bouncy Castle, and I would prefer not to implement a custom handler from scratch since this is a small project.