Indexer Optimizations
Optimisation options are displayed as a system message and in Index management.
Disable Product EAV Index
According to Adobe documentation, it is advisable to deactivate the EAV Index product for performance reasons. However, this should only be done if no flat indices are used or if a different catalogue search is used instead of OpenSearch or ElasticSearch.
The index can be easily deactivated via configuration under Stores > Settings > Configuration > Catalog > Catalog > Catalog Search > Enable EAV Indexer
Configure parallel mode
Some of the indexers can be executed in parallel. The dimensions and settings can be found in the Adobe documentation.
To process the price index in parallel, it must be configured via CLI. Pacemaker Indexer provides the appropriate recommendation for your shop.
The CLI command is:
bin/magento indexer:set-dimensions-mode catalog_product_price <MODE>
Set Indexer Thread Count
To really execute parallelize indexers in several processes, the variable MAGE_INDEXER_THREADS_COUNT must be used. This can be specified in env.php.
Please refer to the Adobe documentation