Leaflet distinguishing sublayers within one GeoJSON layer

I would like to have more than one layer within one existing GeoJSON layer.

I found some example here:

http://www.gistechsolutions.com/leaflet/DEMO/sports/sports.html

which refers to one .json file and afterwards the features are collected from the properties.

I was trying on my code do something more simple, as I want to have the same colour, but only smaller radius of my icon.

My GeoJSON code looks like this:

 var sitec = {
    "type": "FeatureCollection",
        features: [
            {
             type: "Feature",
             "properties": {
                 "Title": "Sitec IS",
                 "Head": "7400 Beach Drive",
                 "Description": "Gavin Sinclair",
                 "Value":2
        },
            "geometry": {
            "type": "Point",
            "coordinates": [
            0.16964435577392578,
            52.29220753602784
                ]
                  }
                    },
 {
  "type": "Feature",
  "properties": {
"Title": "JHG",
    "Head": "Shortstanton sidings",
"Description": "Conor Murphy",
"Value":1,
"URL": "<a href='https://www.johnhenrygroup.co.uk/' target='blank'>JHG</a>",
"Pict": "image.png"
 },
  "geometry": {
    "type": "Point",
    "coordinates": [
      0.05458831787109375,
      52.29163006501503
    ]
  }
 }
              ]
        };

and what I would like to achieve – set the file icon size based on the propeerties.Value but keep it in the same group.

My marker customisation looks like this:

var geojsonMarkerOptions = {
radius: 8,
fillColor: "#ff7800",
color: "#000",
weight: 1,
opacity: 1,
fillOpacity: 0.8
};

and again, I would like to have everything the same, apart from radius, so just in case I set:

var geojsonMarkerOptions3 = {
radius: 2,
fillColor: "#ff7800",
color: "#000",
weight: 1,
opacity: 1,
fillOpacity: 0.8
};

My code looks as follows:

 var sitis = L.geoJSON(sitec, {
pointToLayer: function (feature, latlng) {
feature.properties.myKey = feature.properties.Title + ', ' + 
 feature.properties.Head
feature.properties.Value
label = String(feature.properties.Title)
    return L.circleMarker(latlng, geojsonMarkerOptions).bindTooltip(label, 
  {permanent: true, direction: "center", className: "my- 
  labels"}).openTooltip(); 
  return L.circleMarker(latlng, geojsonMarkerOptions3);  
},
    onEachFeature: function (feature, layer) {
        layer.bindPopup("<h1><u><font color='red'>"+feature.properties.Title+"</h1></u></font><h2>Address: "+feature.properties.Head+"</h2><p>"+feature.properties.Description+"</p><p> Website:"+feature.properties.URL+"</p><br><center><img src='images/" + feature.properties.Pict + " ' style='width:200px;height:300x;'>");

  }
    })
    .addTo(map);

Map remains the same and console says nothing.

Does anyone knows how to do it? Or shall I write all this stuff separately, creating sth like completely new layer?

var sitis = L.geoJSON(sitec, {
//----------------------------- geoJSON style ------------------
   style: function(feature) {
    if (feature.properties.Value === "1") {
    return {
        fillColor: "#ff7800",
        radius: 8
        };
    }
    if (feature.properties.Value == "2") {
    return {
        radius: 4
        };
    }
},
 //-----------------------------geoJSON style code -------------------
pointToLayer: function (feature, latlng) {
feature.properties.myKey = feature.properties.Title + ', ' + feature.properties.Head
label = String(feature.properties.Title)
    return L.circleMarker(latlng, geojsonMarkerOptions).bindTooltip(label, 
 {permanent: true, direction: "center", className: "my-labels"}).openTooltip(); 
//https://gis.stackexchange.com/questions/245621/how-to-label-geojson-points-in-leaflet
   },
       onEachFeature: function (feature, layer) {
        layer.bindPopup("<h1><u><font color='red'>"+feature.properties.Title+"</h1> 
</u></font><h2>Address: "+feature.properties.Head+"</h2> 
 <p>"+feature.properties.Description+"</p><p> Website:"+feature.properties.URL+"</p> 
 <br><center><img src='images/" + feature.properties.Pict + " ' 
  style='width:200px;height:300x;'>");
        layer.on({                          // mouse hover features
            mouseover: function () {
                this.setStyle({
                    'fillColor': '#b45501',
                });
            },
            mouseout: function () {
                this.setStyle({
                    'fillColor': '#ff7800',
                });
            }

        });
 }
    })
    .addTo(map);