Search rate and index latency is high and showing high response

I'm using elasticsearch as database but I'm facing momentary surge in search rate and latency. Can anyone tell why there is a high search rate and latency observerd I have 10 nodes of cluster which are physical vms. It's working fine as of now but and but it keeps happening once in a whole day. I have increased the threadpool and heap memory both but didn't help.

java.lang.Thread.run(Thread.java:748)
Suppressed: org.elasticsearch.client.ResponseException: method [POST], host [http://172.24.44.41:9200], URI [/cmsentitydb_20210215/_search?routing=83&typed_keys=true&ignore_unavailable=false&expand_wildcards=open&allow_no_indices=true&ignore_throttled=true&search_type=query_then_fetch&batched_reduce_size=512&ccs_minimize_roundtrips=true], status line [HTTP/1.1 429 Too Many Requests]{"error":{"root_cause":[{"type":"circuit_breaking_exception","reason":"[parent] Data too large, data for [<http_request>] would be [33441913798/31.1gb], which is larger than the limit of [32641751449/30.3gb], real usage: [33441913216/31.1gb], new bytes reserved: [582/582b], usages [request=16472/16kb, fielddata=1771/1.7kb, in_flight_requests=17221480/16.4mb, model_inference=0/0b, eql_sequence=0/0b, accounting=4393158/4.1mb]","bytes_wanted":33441913798,"bytes_limit":32641751449,"durability":"TRANSIENT"}],"type":"circuit_breaking_exception","reason":"[parent] Data too large, data for [<http_request>] would be [33441913798/31.1gb], which is larger than the limit of [32641751449/30.3gb], real usage: [33441913216/31.1gb], new bytes reserved: [582/582b], usages [request=16472/16kb, fielddata=1771/1.7kb, in_flight_requests=17221480/16.4mb, model_inference=0/0b, eql_sequence=0/0b, accounting=4393158/4.1mb]","bytes_wanted":33441913798,"bytes_limit":32641751449,"durability":"TRANSIENT"},"status":429}