You will need a Windows license. Parallels is a "virtual machine" system. The virtual machine needs to be running an operating system, in this case, Windows, in order for SwordSearcher to work. There is no way to run SwordSearcher without an operating system. Any virtual machine you use would have to be running Windows in order to use SwordSearcher.
I have tried many ways with both Linux and OSX to get SS working with varying amounts of success. Logos is just way to bulky and costly for the layman bible study, so Amazon and Alldocube to the rescue, for about $400 I have a home for my SS and bible study again. I officially am done with trying to re invent the wheel. Oh and I use my Mac for everything else...
I am now running SwordSearcher under Parallels on a Mac.
In Dec. of 2022, I bought another license to Windows 10 and used it on this Virtual Machine. I found the kinguin.net website based on a recommndation here: https://www.tomshardware.com/reviews/get-windows-10-free-or-cheap,5717.html. They seemed to offer the least expensive Win10 license that was really legit (I knew nothing about critiques of kinguin.net when I bought it from there, but it turned out my license was perfectly OK.) The tomshardware.com review also said to buy a license that allows for online activation (I did not know there were some that did not allow that!), so that’s what I got. The license I got is an OEM license, since I went to command prompt and typed in “slmgr -dli” as recommended in the comments to the above link, and that’s what it came back as.