How to select keywords for SEO promotion / contextual advertising on Google?

Question

Google

Tell me, please, how to analyze and select keywords for SEO promotion and contextual advertising on Google and with what tool?
At the moment I use only the Google keyword planner - I look at the frequency, synonyms, etc.
But when choosing keywords, I noticed that the difference in the frequency of the requested words between the Google planner and Yandex Wordstat varies greatly: for example, the keyword "mini tractor buy prices" in the planner has a frequency of "-", i.e. zero, and in wordstat - 614 requests per month (in Ukraine).
1) Does it make sense to use data on the frequency and synonyms of Wordstat for promotion in Google? 2) Which of these tools can be trusted more? 3) Are there any other working tools for selecting words (preferably free) for promotion/advertising on Google?

Answer 1

1) Does it make sense to use data on the frequency and synonyms of Wordstat for promotion in Google?

Synonyms yes, frequency no.
Vasya says that 30 people go to his cafe. Petya says that 50 people visit him. Which one of them should I trust? Both. They both do not lie - the popularity of the cafe is different. Also, the popularity of search engines is different.
There are a lot of tools - KeyCollector, Bukvaris, the only thing is that there is such a thing as the "Low impressions" status, in which the keyword does not work. And almost all keywords without this status are in the Planner.
Summary: words can be taken from anywhere, but they most likely will not work in Google, because. will fall into the "Low impressions" status.

Answer 2

you can look at Bookvarix at
least 50% of requests to search engines - these are long tail , low-frequency
ones, so you should select those that best match the landing page