Cloudwatch alarm setup to track concurrent sftp sessions in aws/transfer

I'm trying to track the number of concurrent user sftp sessions within aws transfer usage. As there are limits to the number of users and unique sessions within a single connection, customer prefer to have monitoring and alarms to manage user connections and sessions. Cloudwatch AWS/Transfer metrics do not have this metric for tracking out of the box. I was able to use a CW log insights query filters to find the number of unique sessions, something like below query. But I'm not able to find an easy way to use this query as a metric filter against the aws/transfer log group and create alarms on top of it. Appreciate any ideas on how to get this requirement to work.

fields @timestamp, @message | filter @message like /CONNECTED/ | parse @message '"activity-type":""' as activityType | filter activityType in ["CONNECTED"] | parse @message '"user":""' as user | parse @message '"session-id":"*"' as sessionId | sort @timestamp desc | stats count_distinct(sessionId) as sessionCount by user | sort sessionCount desc