How to use Newtonsoft JSON serializer for all Flurl 4.0 calls globally or per specific client

I need to use Newtonsoft JSON serializer for all calls made via Flurl 4.0 (or at least for all calls made by a specific Flurl client), but I cannot figure out how to set it up. From the answer to the FLURL 4.0 use Newtonsoft JSON Serializer on a single request question, I see how to do it for each call, but this seems a bit tedious, since I would need to use the same settings for all calls. What is the correct way to (a) set it globally (i.e. not tied to a specific client) and (b) set it for all requests made by a given client? To create a client I use the following helper method:

public static IFlurlClient Create
(
    string url,
    string? proxy = null
)
{
    IFlurlClient client = string.IsNullOrEmpty(proxy)
        ? new FlurlClient(url)
        : new FlurlClientBuilder(url)
            .ConfigureInnerHandler(h => {
                h.Proxy = new WebProxy(proxy);
                h.UseProxy = true; })
            .Build();

    return client;
}

What do I need to inject into this method to make it work with Newtonsoft JSON serializer?

First install the Newtonsoft serializer from NuGet.

If you just need it to work with the client you created in your code:

client.Settings.JsonSerializer = new NewtonsoftJsonSearializer();