After some trial and error, I have gotten to this body:
{"__metadata":{"type":"SP.Publishing.SitePage"},"LayoutWebpartsContent":"[{\"id\":\"cbe7b0a9-3504-44dd-a3a3-0e5cacd07788\",\"instanceId\":\"cbe7b0a9-3504-44dd-a3a3-0e5cacd07788\",\"title\":\"\\n Title area\\n \",\"description\":\"\\n Title area description\\n \",\"audiences\":[],\"serverProcessedContent\":{\"htmlStrings\":{},\"searchablePlainTexts\":{},\"imageSources\":{\"imageSource\":\"/_LAYOUTS/IMAGES/SLEEKTEMPLATEIMAGETILE.JPG\"},\"links\":{},\"customMetadata\":{\"imageSource\":{}}},\"dataVersion\":\"1.4\",\"properties\":{\"imageSourceType\":2,\"title\":\"@{outputs('Get_message_details')?['body/subject']}\",\"textAlignment\":\"Left\",\"showPublishDate\":false,\"authors\":[],\"showTopicHeader\":false,\"authorByline\":[],\"layoutType\":\"CutInShape\",\"titlePlaceholder\":\"Name your news post\",\"topicHeader\":\"\",\"hasTitleBeenCommitted\":false},\"reservedHeight\":306}]","AuthorByline":[],"TopicHeader":"","Title":"@{outputs('Get_message_details')?['body/subject']}","BannerImageUrl":"/_layouts/15/images/sitepagethumbnail.png","CanvasContent1":"[{\"controlType\":4,\"id\":\"1212fc8d-dd6b-408a-8d5d-9f1cc787efbb\",\"position\":{\"controlIndex\":2,\"sectionIndex\":1,\"sectionFactor\":12,\"zoneIndex\":1,\"layoutIndex\":1},\"addedFromPersistedData\":true,\"emphasis\":{},\"innerHTML\":\"@{outputs('Compose')}\"},{\"controlType\":0,\"pageSettingsSlice\":{\"isDefaultDescription\":true,\"isDefaultThumbnail\":true}}]","Categories":""}
Which outputs this:
{"__metadata":{"type":"SP.Publishing.SitePage"},"LayoutWebpartsContent":"[{\"id\":\"cbe7b0a9-3504-44dd-a3a3-0e5cacd07788\",\"instanceId\":\"cbe7b0a9-3504-44dd-a3a3-0e5cacd07788\",\"title\":\"\\n Title area\\n \",\"description\":\"\\n Title area description\\n \",\"audiences\":[],\"serverProcessedContent\":{\"htmlStrings\":{},\"searchablePlainTexts\":{},\"imageSources\":{\"imageSource\":\"/_LAYOUTS/IMAGES/SLEEKTEMPLATEIMAGETILE.JPG\"},\"links\":{},\"customMetadata\":{\"imageSource\":{}}},\"dataVersion\":\"1.4\",\"properties\":{\"imageSourceType\":2,\"title\":\"Test nº 999\",\"textAlignment\":\"Left\",\"showPublishDate\":false,\"authors\":[],\"showTopicHeader\":false,\"authorByline\":[],\"layoutType\":\"CutInShape\",\"titlePlaceholder\":\"Name your news post\",\"topicHeader\":\"\",\"hasTitleBeenCommitted\":false},\"reservedHeight\":306}]","AuthorByline":[],"TopicHeader":"","Title":"Test nº 999","BannerImageUrl":"/_layouts/15/images/sitepagethumbnail.png","CanvasContent1":"[{\"controlType\":4,\"id\":\"1212fc8d-dd6b-408a-8d5d-9f1cc787efbb\",\"position\":{\"controlIndex\":2,\"sectionIndex\":1,\"sectionFactor\":12,\"zoneIndex\":1,\"layoutIndex\":1},\"addedFromPersistedData\":true,\"emphasis\":{},\"innerHTML\":\"{"@odata.context":"https://graph.microsoft.com/v1.0/$metadata#teams('9893b60b-98f1-479a-a274-71cabc0e8a18')/channels('19%3AXg-phSCY-kuv4pLCT-o8vuLDufrKkm_ho0dBmw-0Wvo1%40thread.tacv2')/messages/$entity","id":"1650377165586","replyToId":null,"etag":"1650377165586","messageType":"message","createdDateTime":"2022-04-19T14:06:05.586Z","lastModifiedDateTime":"2022-04-19T14:06:05.586Z","lastEditedDateTime":null,"deletedDateTime":null,"subject":"Test nº 999","summary":null,"chatId":null,"importance":"normal","locale":"en-us","webUrl":"https://teams.microsoft.com/l/message/19%3AXg-phSCY-kuv4pLCT-o8vuLDufrKkm_ho0dBmw-0Wvo1%40thread.tacv2/1650377165586?groupId=9893b60b-98f1-479a-a274-71cabc0e8a18&tenantId=ce0df492-7f32-43cf-b297-ee135760da1b&createdTime=1650377165586&parentMessageId=1650377165586","policyViolation":null,"eventDetail":null,"from":{"application":null,"device":null,"user":{"id":"a7fcb8b1-a5cc-4133-9756-f48cfff228d6","displayName":"Flavio Neto","userIdentityType":"aadUser"}},"body":{"contentType":"html","content":"<div>\n<div itemprop=\"copy-paste-block\">\n\n<div style=\"font-size:14px\">\n\n<p><span style=\"font-size:12pt\"><span>Hi everyone!</span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span></span></span> </p>\n\n\n\n<p><span style=\"font-size:12pt\"><span>In our effort to streamline our working relationships, I would like to ask everyone to start using this team’s calendar to note down anything that might impact the whole team like, for example, create a recurring event regarding when you are regularly away from your desk, or working in another personal projects or jobs. </span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span>As most of us have different work schedules, sometimes radically so, it would help us as a team to share those timings and lay them out. </span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span>I would also ask for everyone to put down their annual leave dates and any other team relevant events. </span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span>Of course, you can still access other people’s personal calendars, and see their availability, but this method can give us, briefly, an idea of how much of our team is available and when.</span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span></span></span> </p>\n\n\n\n<p><span style=\"font-size:12pt\"><span> Please see mine and Adam’s entries in the calendar as an example.</span></span></p>\n\n\n\n<p><span style=\"font-size:12pt\"><span> #NEWS</span></span></p>\n\n</div>\n</div>\n</div>","plainTextContent":"\n\n\n\n\nHi everyone!\n\n\n\n \n\n\n\nIn our effort to streamline our working relationships, I would like to ask everyone to start using this team’s calendar to note down anything that might impact the whole team like, for example, create a recurring event regarding when you are regularly away from your desk, or working in another personal projects or jobs. \n\n\n\nAs most of us have different work schedules, sometimes radically so, it would help us as a team to share those timings and lay them out. \n\n\n\nI would also ask for everyone to put down their annual leave dates and any other team relevant events. \n\n\n\nOf course, you can still access other people’s personal calendars, and see their availability, but this method can give us, briefly, an idea of how much of our team is available and when.\n\n\n\n \n\n\n\n Please see mine and Adam’s entries in the calendar as an example.\n\n\n\n #NEWS\n\n\n\n"},"channelIdentity":{"teamId":"9893b60b-98f1-479a-a274-71cabc0e8a18","channelId":"19:Xg-phSCY-kuv4pLCT-o8vuLDufrKkm_ho0dBmw-0Wvo1@thread.tacv2"},"attachments":[],"mentions":[],"reactions":[],"messageLink":"https://teams.microsoft.com/l/message/19%3AXg-phSCY-kuv4pLCT-o8vuLDufrKkm_ho0dBmw-0Wvo1%40thread.tacv2/1650377165586?groupId=9893b60b-98f1-479a-a274-71cabc0e8a18&tenantId=ce0df492-7f32-43cf-b297-ee135760da1b&createdTime=1650377165586&parentMessageId=1650377165586","threadType":"channel","teamId":"9893b60b-98f1-479a-a274-71cabc0e8a18","channelId":"19:Xg-phSCY-kuv4pLCT-o8vuLDufrKkm_ho0dBmw-0Wvo1@thread.tacv2"}\"},{\"controlType\":0,\"pageSettingsSlice\":{\"isDefaultDescription\":true,\"isDefaultThumbnail\":true}}]","Categories":""}
But still creates pages like this:
