How accurate are keyword tools in analyzing expected traffic?

When researching niches, I often stumble across potential long-tail keywords with 10k+ searches and weak af first-rank pages. But before diving in, I want to know how reliable these tools' estimates are. Does anyone know how accurate "keywordtool.io" is? Also, if you know of any other tools that are more accurate, or less expensive, please let me know in this thread.

Having worked with keyword research tools for over 5 years, Non has fixed analyzed data but there are few close to perfect; Ahrefs, Kwfinder, and GKP.
If it's just a single keyword and you're okay sending it down to my PM.

I can have it plugged on Ahrefs and KWfinder getting the estimated traffic for you.

It is hard to say, as every person has their own opinion.
I can post own:

I found 1 easy keyword which has following monthly search volumes:
Google keyword planner - 10M
Semrush - 40M
KWFinder - 40M
Ahrefs- 2k

First 2 google results monthly traffic according Ahrefs - 400.
In SERP's there are no competition at all.
Semrush also shows several hundreds of monthly traffic to first google results.

After that i have my opinion in that kw tool i can trust.

I've been playing around this area a lot past few months. After google - ahrefs has the most accurate data.

KWFinder gets most of its data (specially backlink data) from Majestic. KWfinder difficulty is just a combination of TF/CF/DA/PA of the top10 SERP results.

Don't get overly attached to the info you get from the tools. Especially the search volume. Use is more like an estimate. Most often the actual number is a lot more.

Numbers were always rounded up to the nearest thousand and they're only estimates anyway – not precise figures,

It depends, for example semrush is accurate for 2-3 months, but sometimes you can experience a completely different reality like focusing keywords on Google that are 1-2k/months but in reality 50-60k. Only Search Console data is accurate.