The question is, how good are the free tools?
Owners the paid tools also often have expensive equipement to to do measurements and verify the results. They will report back results for fixes or want their money back.
Users of free tools often are not able to measure correctly and therefore cannot even compare results.
Then again, if nobody starts to use the free tools, we will never know any shortcomings.
One tool I heard of that may be able to do it is elmer (
https://www.csc.fi/web/elmer ) and OpenEMS
https://openems.de/start/index.php