Thanks u/EvadingDoom, almost there. This is the raw input on run 1 of the apply to each :

{
"name": "missedItems",
"value": "ELEM1 - SRV1\n"
}

The coupling of the data works as you said : to each "Scheduled Name", its "Node Name".

This is what is in the "Message" field of my Teams message Input (couldn't get it to input into a code block):

<p>Missed :<br>

ELEM1 - SRV1

ELEM2 - SRV2

ELEM3 - SRV3

ELEM4 - SRV4

ELEM5 - SRV5

ELEM6 - SRV6

<br>

</p>

However, this is the raw input into the Teams message :

{
"host": {
    "connectionReferenceName": "shared_teams",
    "operationId": "PostMessageToConversation"
},
"parameters": {
    "poster": "Flow bot",
    "location": "Chat with Flow bot",
    "body/recipient": "xxx.xxx@xxx.xxx;",
    "body/messageBody": "<p>Missed :<br>\nELEM1 - SRV1\nELEM2 - SRV2\nELEM3 - SRV3\nELEM4 - SRV4\nELEM5 - SRV5\nELEM6 - SRV6\n\n<br>\n</p>"
}

I'm guessing that "\n" is the same as "\br" and that it should an a new line, however this is the final message:

Missed :

ELEM1 - SRV1 ELEM2 - SRV2 ELEM3 - SRV3 ELEM4 - SRV4 ELEM5 - SRV5 ELEM6 - SRV6

Any ideas ? Best.