Hi KatakiaAkshara-9774, welcome to Microsoft Q&A forum. We will be glad to assist you there.
If you want to set the ttl at the container level, you need to add it in the body like below. Please note here I am creating a new collection with 'tempcoll' name and ttl defined as 150 seconds.
{
"id": "tempcoll",
"defaultTtl": 150
}
When I check it on Azure Portal, its set correctly as below screenshot:
I used Postman to post the rest api requests.
Please let us know if this helps or else we can discuss more on the same.
----------
if this solves your query, please "Accept Answer" as it could help others having similar issue.