There are only two tool I recommended, Ahrefs(First choice) and Semrush(Second choice). Others are just awful and don’t have their own crawler to create their own database.They just use keyword planner data with basic filter.
Other blogs recommended it because they get commission, never thought like you’ve not used those tools hence you did not get success, it’s just myth.
And Keyword difficulty is not always accurate on any tool. You should buy only those tools, who have their own crawler, I mean how they create their own database, if other tool just give you metrics number randomly or from other source like majestic then don’t believe on it. I already recommended which are good, but if you think their price is high, then you can use group buy service like Flikover dot com.