Strange it must not have been posted.
Anyway, yes I did try the dynamic content route first as this article explained https://www.ariclevin.com/Flow/Post/outlook-events-onedrive-excel
This is the dynamic content way.



The output error sais wrong date format:
{"statusCode":400,"headers":{"Pragma":"no-cache","x-ms-request-id":"4934d0b8-198f-44aa-8fc4-637bfde4bf19","Strict-Transport-Security":"max-age=31536000; includeSubDomains","X-Content-Type-Options":"nosniff","X-Frame-Options":"DENY","Cache-Control":"no-store, no-cache","Set-Cookie":"ARRAffinity=2dec40ee271a11b22b991f97343df846ec15685ecd916e17e0cdc237e9bff764;Path=/;HttpOnly;Secure;Domain=office365-ne.azconn-ne-01.p.azurewebsites.net,ARRAffinitySameSite=2dec40ee271a11b22b991f97343df846ec15685ecd916e17e0cdc237e9bff764;Path=/;HttpOnly;SameSite=None;Secure;Domain=office365-ne.azconn-ne-01.p.azurewebsites.net","Timing-Allow-Origin":"*","x-ms-apihub-cached-response":"true","Date":"Mon, 26 Oct 2020 19:46:59 GMT","Content-Length":"289","Content-Type":"application/json","Expires":"-1"},"body":{"status":400,"message":"String was not recognized as a valid DateTime.\r\nclientRequestId: 4934d0b8-198f-44aa-8fc4-637bfde4bf19","error":{"message":"String was not recognized as a valid DateTime."},"source":"office365-ne.azconn-ne-01.p.azurewebsites.net"}}
The input and output in a compose is:
Input:
va[{"@odata.etag":"","ItemInternalId":"86df82b7-140c-48f9-8308-f4f66f070ac2","eventName":"Historia","startDate":"43831","endDate":"43831","arskurs":"8A","rooms":"13"}]
Output:
va[{"@odata.etag":"","ItemInternalId":"86df82b7-140c-48f9-8308-f4f66f070ac2","eventName":"Historia","startDate":"43831","endDate":"43831","arskurs":"8A","rooms":"13"}]