You can disable the pluralization plugin. Go to (in the designer) Tools -> Bind Designer events to plugins, then select with 'Designer event' 'NameSingularToPluralConversion' and uncheck the 'IsEnabled' checkbox.
This also controls the pluralization of names on e.g. navigators etc. The downside of this is that the plugin is disabled for all the projects you load, so if you work on multiple projects this might be less ideal.
You can also adjust the pluralization plugin code, if you want to. The plugin sourcecode comes with the sourcecode archive available under My account -> v5.5 -> Extras section on the website. In the plugins folder, you'll find the Inflector.cs file which is the root of this plugin, it's a bunch of simple regexps which you can e.g. alter to make it work for Dutch (but as Dutch' pluralization rules aren't that simple, this likely is a daunting task).
A 3rd way to solve this is by using a custom Context template for code generation. after you've loaded your project in the designer, click the Template bindings viewer icon in the toolbar (tools -> template bindings viewer). Then double click the SD_EF_Core_Context binding. At the bottom of the template, you'll see:
public DbSet<<%=entity.Name%>> <%=GeneratorUtils.PluralizeString(entity.Name)%> { get; set; }
Simply remove the call to GeneratorUtils.PluralizeString and you'll get singular names. It's best if you create a copy of the template and bind it to the same template ID (SD_EF_Core_Context) using a new templatebindings file https://www.llblgen.com/Documentation/5.5/Designer/How%20To/TemplatesAdd.htm and give it a higher precedence number than the vanilla one (so it's picked over the vanilla one, it then overrules the templateID binding set by our templatebinding files).