Tried variants on wrapping in @() but am getting nowhere. Very confusing and seems the only documentation is this example:

Integration with Grid in ASP.NET Core Template Component Demo | Telerik UI for ASP.NET Core

<grid-detail-template>
    <kendo-datasource name="ds-${data.DeviceId}" type="DataSourceTagHelperType.Ajax" server-filtering="true" is-in-client-template="true">
        <transport>
            <read url="@Html.Raw("/Devices/Diagnostics/${data.DeviceId}?handler=Read")" type="post" data="forgeryToken" />
        </transport>
        <filters>
            <datasource-filter logic="and">
                <filters>
                    <datasource-filter field="DeviceId" operator="eq" value="@("${data.DeviceId}")"></datasource-filter>
                    <datasource-filter field="LogDate" operator="gt" value="@DateTime.Today.AddMonths(-1)"></datasource-filter>
                </filters>
            </datasource-filter>
        </filters>
        <schema>
            <model>
                <fields>
                    <field name="DeviceId" type="number" />
                    <field name="LogDate" type="date" />
                </fields>
            </model>
       </schema>
</kendo-datasource>
<kendo-chart name="memChart" theme="Bootstrap" datasource-id="ds-${data.DeviceId}">
</kendo-chart>

section id="main" class="PageSection">
            @(Html.Kendo().TabStrip()
        .Name("tabstrip")
        .Events(events => events
            .Select("onTabSelected")
            .Activate("onTabActivated")
            .ContentLoad("onTabContentLoaded")
            .Error("onTabError")
        )
        .Animation(animation =>
        {animation.Enable(false);})
        .Items(tabstrip =>
        {
            if (!ViewBag.isOffline)
            {
                tabstrip.Add().Text("Home")
                .HtmlAttributes(new { id = "hometabid" })
                .Selected(true)
                .ImageUrl(Url.Content("~/Content/Images/HomeTabIcon.png")).ImageHtmlAttributes(new { id = "hometabimgid" })
                .Content(@<text>
                            @RenderSection("HomeTab", false)
                        </text>).ContentHtmlAttributes(new { @style = "overflow: auto;" });
            }
            tabstrip.Add().Text("Lead Search")
                .HtmlAttributes(new { id = "LeadSearchtabid" })
                .Selected((bool)ViewBag.isOffline).ContentHtmlAttributes(new { @style = "overflow: auto;" })
                .ImageUrl(Url.Content("~/Content/Images/search-lead-icon.png")).ImageHtmlAttributes(new { id = "leadsearchtabimgid" })
                .Content(@<text>
                    @Html.Partial("LeadSearching")
                </text>);
           if (ViewBag.isOffline)
            {
                tabstrip.Add().Text("VoiceMail")
                .HtmlAttributes(new { id = "vmtabid" })
                .Selected(false)
                .ImageUrl(Url.Content("~/Content/Images/HomeTabIcon.png")).ImageHtmlAttributes(new { id = "hometabimgid" })
               .Content(@<text>
                            @Html.Partial("VoiceMail")
                </text>).ContentHtmlAttributes(new { @style = "overflow: auto;" });
            }
        }))
            @RenderBody()
            <div id="dvNotification"></div>
        </section>

@(Html.Kendo().Grid<Project>()
    .Name("ProjectsGrid")
    .Columns(columns =>
    {
        columns.Bound(p => p.ProjectName)
            .ClientTemplate("<a href=/Directory/project/${Id} target=_blank>${ProjectName}</a>")
            .Width(180);
        columns.Bound(p => p.ProjectManager).Width(230)
            .ClientTemplate("#=data.ProjectManager?.Name#")
            .EditorTemplateName("WorkingEmployee")
            .Sortable(s => s.Compare("(a, b) => compareManager(a, b)"));
        columns.Bound(p => p.IsActive)
            .Width(180)
            .ClientTemplate("#: IsActive ? 'Yes' : 'No' #");
    })
    .ToolBar(toolbar =>
    {
        toolbar.Save();
        toolbar.Search();
    })
    .Search(s =>
    {
        s.Field(e => e.IsActive);
        s.Field(e => e.ProjectName, "contains");
    })
    .Sortable()
    .Editable(GridEditMode.InCell)
    .DataSource(dataSource => dataSource
        .Ajax()
        .Batch(true)
        .ServerOperation(false)
        .Events(events => events.Error("error_handler"))
        .Model(model =>
        {
            model.Field(p => p.ProjectManager).DefaultValue(
                ViewData["defaultProjectManager"] as User);
            model.Field(p => p.ProjectName).Editable(false);
        })
        .Read("Projects_Read", "Directory")
        .Update("Projects_Update", "Directory")
    ))

Uncaught TypeError: e.charAt is not a function kendo.all.js:2114

<script id="ApproveOrDenyTemplate" type="text/x-kendo-template">
    @(Html.Kendo().RadioGroupFor(model => model.ApproveOrDeny)
        .Layout(RadioGroupLayout.Horizontal)
        .HtmlAttributes(new { style = "display: inline-flex; vertical-align: top;" })
        .LabelPosition(RadioGroupLabelPosition.After)
        .Items(i =>
        {
            i.Add().Label("Approve").Value("Approve");
            i.Add().Label("Deny").Value("Deny");
        })
        .Events(e => e.Change("changeApproveOrDeny"))
        .ToClientTemplate()
    )
</script>

items.Add()
    .TemplateId("ApproveOrDenyTemplate")
    .Hidden(!Model.ShowApprovalRadioGroup);

VM48:1 Uncaught SyntaxError: Unexpected token '<'
kendo.syncReady(function(){jQuery("\#ApproveOrDeny").kendoRadioGroup({"change":changeApproveOrDeny,"items":[{"label":"Approve","value":"Approve"},{"label":"Deny","value":"Deny"}],"value":"Approve","layout":"horizontal","labelPosition":"after"});});<\/script>

var uploader = _helper.Kendo().Upload()
                .Name("uploadFiles")
                .Multiple(true)
                .HtmlAttributes(new { style = "margin: 15px 0 5px 0;" });

Error	CS1061	'IHtmlHelper' does not contain a definition for'Kendo'
and no accessible extension method 'Kendo' accepting a first argument of 
type'IHtmlHelper' could be found (are you missing a using directive or an assembly reference?)