This is continuation of ZBX-21537, as in latest version pointers to items are stored on hosts, it is possible to avoid iterating over items and searching for hosts but just iterate over host and to get item to improve performance.
Tested with 1million items and 1million triggers and it took 0.194315 after this improvement, while with just ZBX-21537 it was 0.321998

Patch attached:
ZBX-21733-6.3.diff