Atlas search with conditions and why MUST works faster than SHOULD and followed by other?

@Aasawari, Thank you so much for your quick response! My goal is to search keywords based on user input, I mean I need to search AND, OR, and single-term searches, I tried to find some example and implement it in the search but not much help as the query is slow,

I tried executionstats() and explain() to check the execution time

Could you please give 3 examples based on the below document on AND which is MUST, OR which is SHOULD, and single-term search separate queries, as I found it a little confusing while seeing some examples in the docs?

I am using fulltext index (atlas search index), I am trying to search words from 3 fields which are the headline, fulltext, subtitle

{
    "_id": {
        "$oid": "6368ca3fcb0c042cbc5b198a"
    },
    "articleid": "159447148",
    "headline": "T20 World Cup: Zomato’s Epic ",
    "subtitle": "Response To ‘Cheat Day’ Remark Is Unmissable",
    "fulltext": "The trade began on October 21",
    "article_type": "online",
    "pubdate": "2022-11-07"
}