@Yuriy L Thank you for your post and I apologize for the delayed response.
Unfortunately, Azure Cost Management doesn't expose Cosmos DB costs down to the container/collection level. This is feature in work with no confirmed ETA.
The formula to use to convert provisioned throughput into monthly $ costs depends whether you're using autoscale or not.
For autoscale: <throughput> / 100 * 0.012 * 730
For manual provisioned throughput: <throughput> / 100 * 0.008 * 730
Hope this helps!
----------------------------------------------------------------------------------------------------------------------
If the response helped, do "Accept Answer" and up-vote it