Ahrefs VS KWFinder

For keyword research, Semrush is good.

KWfinder is a solid option that will give you great value for the money, but I have to agree with what others said - Ahrefs is overall the better of the two.
Still, KWfinder has shown to be reliable when it comes to determining keyword difficulty, so if that’s what you need, it’s a reason to use it in addition to Ahrefs. It will offer you a different perspective, but whether or not that would be worth the additional subscription is up to you.
As far as everything else goes, though, Ahrefs will always outperform KWfinder.

Semrush and Ahrefs both work fine

Ahrefs is better

I don't really use Ahrefs for keyword research. I use KWfinder to search for keywords and use ahrefs to manually check the competiton by looking at the backlinks of top sites.

Ahrefs too have the option to check country wise, KWfinder too fine on LSIs. I have used both, anyhow you should try with both so you can know the real results. Both are fine in my experience.