Indexing requests and time goes high on 1 node in cluster

Hi Team

I am using ES 7.17.1. Pushing logs from Fluent to 5 node cluster. Enabled xpack monitoring on ES. we observe that sometime during the day the indexing requests & indexing time goes very high on a single node. Sometimes, the indexing count is same on all nodes, but 1 of the node takes high indexing time leading to cpu saturation and wait queue.

How can I find out which indexes are getting more requests on a particular node and what it the RCA for slow indexing speed.

below is the setting in index template

"number_of_shards": "5",
"number_of_replicas": "0"
"routing": {
      "allocation": {
        "total_shards_per_node": "1"