I'm not certain, but you can probably do something like the views\grid\editors\rte.cshtml does maybe?

it currently does this

@using Umbraco.Cms.Core.Templates
@model dynamic
@inject HtmlLocalLinkParser HtmlLocalLinkParser;
@inject HtmlUrlParser HtmlUrlParser;
@inject HtmlImageSourceParser HtmlImageSourceParser;

@{
    var value = HtmlLocalLinkParser.EnsureInternalLinks(Model?.value.ToString());
    value = HtmlUrlParser.EnsureUrls(value);
    value = HtmlImageSourceParser.EnsureImageSources(value);
}

@Html.Raw(value)

I tried this in appsettings but don't works.

 "RichTextEditor": {
          "CustomConfig": {
            "entity_encoding": "raw",
            "relative_urls": false
          },
       }

is working on a reply...