Elasticsearch low indexing speed - wordpress

Question

I have a blog that contains 14k posts and tried to add these posts to the elastic search index.
I indexed some of the posts, but it's extremely slow, and it will take about 6 hours to estimate. All the performance optimization tips from the official site I made. In my opinion, I removed the redundant data such as post meta. Can I increase indexing speed? Add the index configuration below:
{
"test-post-1" : {
"aliases" : { },
"mappings" : {
"date_detection" : false,
"properties" : {
"ID" : {
"type" : "long"
},
"guid" : {
"type" : "keyword"
},
"menu_order" : {
"type" : "long"
},
"permalink" : {
"type" : "keyword"
},
"post_content" : {
"type" : "text"
},
"post_date" : {
"type" : "date",
"format" : "yyyy-MM-dd HH:mm:ss"
},
"post_excerpt" : {
"type" : "text"
},
"post_id" : {
"type" : "long"
},
"post_mime_type" : {
"type" : "keyword"
},
"post_modified" : {
"type" : "date",
"format" : "yyyy-MM-dd HH:mm:ss"
},
"post_name" : {
"type" : "text",
"fields" : {
"post_name" : {
"type" : "text"
},
"raw" : {
"type" : "keyword",
"ignore_above" : 10922
}
}
},
"post_parent" : {
"type" : "long"
},
"post_status" : {
"type" : "keyword"
},
"post_title" : {
"type" : "text",
"fields" : {
"post_title" : {
"type" : "text",
"analyzer" : "standard"
},
"raw" : {
"type" : "keyword",
"ignore_above" : 10922
},
"sortable" : {
"type" : "keyword",
"ignore_above" : 10922,
"normalizer" : "lowerasciinormalizer"
}
}
},
"post_type" : {
"type" : "text",
"fields" : {
"post_type" : {
"type" : "text"
},
"raw" : {
"type" : "keyword"
}
}
}
}
},
"settings" : {
"index" : {
"mapping" : {
"total_fields" : {
"limit" : "5000"
},
"ignore_malformed" : "true"
},
"number_of_shards" : "1",
"provided_name" : "test-post-1",
"max_shingle_diff" : "8",
"max_result_window" : "1000000",
"creation_date" : "1582745447768",
"analysis" : {
"filter" : {
"shingle_filter" : {
"max_shingle_size" : "5",
"min_shingle_size" : "2",
"type" : "shingle"
},
"edge_ngram" : {
"min_gram" : "3",
"side" : "front",
"type" : "edgeNGram",
"max_gram" : "10"
},
"ewp_word_delimiter" : {
"type" : "word_delimiter",
"preserve_original" : "true"
},
"ewp_snowball" : {
"type" : "snowball",
"language" : "russian"
}
},
"normalizer" : {
"lowerasciinormalizer" : {
"filter" : [
"lowercase",
"asciifolding"
],
"type" : "custom"
}
},
"analyzer" : {
"ewp_lowercase" : {
"filter" : [
"lowercase"
],
"type" : "custom",
"tokenizer" : "keyword"
},
"shingle_analyzer" : {
"filter" : [
"lowercase",
"shingle_filter"
],
"type" : "custom",
"tokenizer" : "standard"
},
"default" : {
"filter" : [
"ewp_word_delimiter",
"lowercase",
"stop",
"ewp_snowball"
],
"char_filter" : [
"html_strip"
],
"language" : "russian",
"tokenizer" : "standard"
}
}
},
"number_of_replicas" : "1",
"uuid" : "cWGjSF4FQ1Or0A_0oSlA2g",
"version" : {
"created" : "7050299"
}
}
}
}
}
Wordpress version: 5.3.2
Elasticsearch version: 7.5.2
Enabled plugins: ElasticPress