No tool is 100% accurate. Yes, they get close to the metrics they showcase.
You can start with Google Keyword Planner. GKP doesn’t offer all detailed information as it used to, unless you spend some money on advertising.
But, you get some decent keyword suggestions with a range of search volumes. Save your long-tail keywords from there and try using Ubersuggest.
It offers a little bit more than basic metrics. For example, competitor’s backlinks (for that keyword).
After saving the basic metrics and competitor’s backinks to your local drive, you can opt for any paid tool like SEMrush, Keyword Revealer, Jaaxy, etc which offer limited amount of tries with their free account.
In case you don’t want to spend on a paid tool. But, if you want to explicitly check the metrics on a paid tool.
I suggest going for the most basic version of Wordtracker, SEMrush, Keyword Revealer, or even Jaaxy.
They get pretty close to the actual scenario. There you go, 2 to 4 tools together can solve your problem.
I have done keyword research this way, and I know this will help you too. If you want to know the best features of the best keyword research tools you can have a look
If you want to learn 17 Best Free Keyword Research Tools To Make Your Life Better