Google Keyword Planner VS Semrush for Search Volume?

Google keyword planner , ofcourse!

Google Keyword Planner only provides very accurate search statistics. It's free, which is a huge plus.
Google should be your first choice if you're looking for a tool to find new keywords to rank for.

SEMrush vs Keyword Planner? One is premium tool and the other is free. Both are great but if you want to get in-depth details and if you want to master keyword research, then yes, SEMrush is definitely for you. Honestly, I would recommend using both the tools.