Sorry for the late response. I never check the notifications and the mail is also easy to miss. When I said we have a mix, I mean some clients within the same project uses Flurl and others use HttpClientFactory. We don't mix the HttpClient create from either. If your project requires high load then I would opt for HttpClientFactory since you have more flexibility there. In the projects that use Flurl for the httpclient, we had inherited from the Flurl.DefaultHttpClientFactory to provide resiliency with Polly and Proxy settings with FlurlHttp.Configure.

        IHttpClientFactory httpClientFactory;
        if (proxySettings == null)
        {
            httpClientFactory = new PollyHttpClientFactory(resiliencyPolicy, ignoreInvalidSslServerCert);
            logger.Information("Setting up http client factory without proxy.");
        }
        else
        {
            httpClientFactory = new ProxyHttpClientFactory(proxySettings, resiliencyPolicy, ignoreInvalidSslServerCert);
            logger.Information("Setting up http client factory with proxy.");
        }

        FlurlHttp.Configure(delegate (GlobalFlurlHttpSettings settings)
        {
            settings.HttpClientFactory = httpClientFactory;
        });