Help with temperature and timebased heating

Hello all, I’m new to NodeRed an trying to wrap my head around it for some days.
My goal is to turn on and off a heating mat so the temperature of my seedlings stays between 25 - 28°C between 08:00 - 18:00 hours.

At the moment my flow looks like this:

corresponding code:

[
    {
        "id": "81a4b5c6169b14e8",
        "type": "tab",
        "label": "Heizmatte Pflanzen",
        "disabled": false,
        "info": "Heizmatte Pflanzen an / ausschalten via \r\nBadezimmer Thermometer und \r\nShellyPlug-4-Universell",
        "env": []
    },
    {
        "id": "81ae0094a1622946",
        "type": "server-state-changed",
        "z": "81a4b5c6169b14e8",
        "name": "HT<26C_5min",
        "server": "9952a067.8c83d",
        "version": 4,
        "exposeToHomeAssistant": false,
        "haConfig": [
            {
                "property": "name",
                "value": ""
            },
            {
                "property": "icon",
                "value": ""
            }
        ],
        "entityidfilter": "sensor.ble_temperature_humtemp5",
        "entityidfiltertype": "exact",
        "outputinitially": true,
        "state_type": "num",
        "haltifstate": "26",
        "halt_if_type": "num",
        "halt_if_compare": "lt",
        "outputs": 2,
        "output_only_on_state_change": false,
        "for": "5",
        "forType": "num",
        "forUnits": "minutes",
        "ignorePrevStateNull": false,
        "ignorePrevStateUnknown": false,
        "ignorePrevStateUnavailable": false,
        "ignoreCurrentStateUnknown": false,
        "ignoreCurrentStateUnavailable": false,
        "outputProperties": [
            {
                "property": "payload",
                "propertyType": "msg",
                "value": "",
                "valueType": "entityState"
            },
            {
                "property": "data",
                "propertyType": "msg",
                "value": "",
                "valueType": "eventData"
            },
            {
                "property": "topic",
                "propertyType": "msg",
                "value": "",
                "valueType": "triggerId"
            }
        ],
        "x": 80,
        "y": 60,
        "wires": [
            [
                "1e7d2eebaa9d67a1",
                "3dc47d4b70261d61"
            ],
            [
                "9055c44074744c9c",
                "e0814726124c4524"
            ]
        ]
    },
    {
        "id": "0becb75158277a92",
        "type": "api-call-service",
        "z": "81a4b5c6169b14e8",
        "name": "Heizmatte_Ausschalten",
        "server": "9952a067.8c83d",
        "version": 5,
        "debugenabled": false,
        "domain": "switch",
        "service": "turn_off",
        "areaId": [],
        "deviceId": [
            "5b9538c56aed01de63d4a21964248abd"
        ],
        "entityId": [],
        "data": "",
        "dataType": "jsonata",
        "mergeContext": "",
        "mustacheAltTags": false,
        "outputProperties": [],
        "queue": "none",
        "x": 590,
        "y": 140,
        "wires": [
            []
        ]
    },
    {
        "id": "001930a28869adca",
        "type": "api-call-service",
        "z": "81a4b5c6169b14e8",
        "name": "Heizmatte_Anschalten",
        "server": "9952a067.8c83d",
        "version": 5,
        "debugenabled": false,
        "domain": "switch",
        "service": "turn_on",
        "areaId": [],
        "deviceId": [
            "5b9538c56aed01de63d4a21964248abd"
        ],
        "entityId": [],
        "data": "",
        "dataType": "jsonata",
        "mergeContext": "",
        "mustacheAltTags": false,
        "outputProperties": [],
        "queue": "none",
        "x": 580,
        "y": 60,
        "wires": [
            []
        ]
    },
    {
        "id": "1e7d2eebaa9d67a1",
        "type": "time-range-switch",
        "z": "81a4b5c6169b14e8",
        "name": "10H",
        "lat": "",
        "lon": "",
        "startTime": "08:00",
        "endTime": "18:00",
        "startOffset": 0,
        "endOffset": 0,
        "x": 290,
        "y": 60,
        "wires": [
            [
                "001930a28869adca"
            ],
            [
                "9055c44074744c9c"
            ]
        ]
    },
    {
        "id": "9055c44074744c9c",
        "type": "api-current-state",
        "z": "81a4b5c6169b14e8",
        "name": "An?",
        "server": "9952a067.8c83d",
        "version": 3,
        "outputs": 2,
        "halt_if": "on",
        "halt_if_type": "str",
        "halt_if_compare": "is",
        "entity_id": "switch.shellyplug4universell",
        "state_type": "str",
        "blockInputOverrides": false,
        "outputProperties": [
            {
                "property": "payload",
                "propertyType": "msg",
                "value": "",
                "valueType": "entityState"
            },
            {
                "property": "data",
                "propertyType": "msg",
                "value": "",
                "valueType": "entity"
            }
        ],
        "for": "0",
        "forType": "num",
        "forUnits": "minutes",
        "override_topic": false,
        "state_location": "payload",
        "override_payload": "msg",
        "entity_location": "data",
        "override_data": "msg",
        "x": 290,
        "y": 140,
        "wires": [
            [
                "0becb75158277a92"
            ],
            []
        ]
    },
    {
        "id": "e0814726124c4524",
        "type": "debug",
        "z": "81a4b5c6169b14e8",
        "name": "<26_False",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 290,
        "y": 240,
        "wires": []
    },
    {
        "id": "3dc47d4b70261d61",
        "type": "debug",
        "z": "81a4b5c6169b14e8",
        "name": "<26_True",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 280,
        "y": 20,
        "wires": []
    },
    {
        "id": "9952a067.8c83d",
        "type": "server",
        "name": "Home Assistant",
        "addon": true
    }
]

The problem is, this flow only works if I manually turn on the wifi plug in the morning and I’m not really sure what I’m missing here so the flow starts automatically, something like this:

If (time between 08:00 - 18:00)
{
If (temperature < 26)
{turn on heating}
if (temperature >28)
{turn off heating} #at the moment solved trough the “5min delay” in the “event: state” type
}
else
{
switch off
}

Thanks in advance for the help!

Seems to me like your trigger isn’t working as expected.
Maybe make it a time trigger that from 08:00 starts checking if your desired temperature range is met and if not either turn on or off the mat?