My setup:

Zabbix Server + 9 Proxy 
All devices SNMP
Backend Elasticsearch

High utilization of History Syncer Internal Processes, and Utilization of LLD worker 

zabbix.conf

• name: ZBX_HISTORYSTORAGEURL
  value: http://es6-lb.elk-6:9200
• name: ZBX_HISTORYSTORAGETYPES
  value: "uint,dbl,str,log,text"
• name: ZBX_STARTDBSYNCERS
  value: "60"
• name: ZBX_CACHESIZE
  value: 4G
• name: ZBX_HISTORYCACHESIZE
  value: 2G
• name: ZBX_HISTORYINDEXCACHESIZE
  value: 2G
• name: ZBX_TRENDCACHESIZE
  value: 2G
• name: ZBX_VALUECACHESIZE
  value: 4G
• name: ZBX_HOUSEKEEPINGFREQUENCY
  value: "0"

I can't figure out how I can reduce the load, where to look for the problem