Windows MikTeX can't find my .sty file

Your local TEXMF tree should not be a subfolder of MiKTeX\texmfs , although it can be a sibling tree as in the screenshot. The key is it ends texmf not texmf\tex\lat...\…

Ideally it should be in an area where you have no user control issues and a common suggestion is C:\users\yourname\mytexmf as similar to ~/mytexmf of Linux. However due to the variety of user names it is better to use something like c:\miktexdata\mytexmf avoiding spaces, punctuation or accented characters.

Once you are sure it looks ok, go to Tasks and Refresh file name database. Exit the console and check MiKTeX is not running in the background. Re-enter MiKTeX console and check the setting is still the same.

IF you are not running console you can do the same from the command line using

initexmf --user-roots=c:\mytexmf --update-fndb=c:\mytexmf --update-fndb

or as suggested in another thread by Ulrike Fischer

initexmf --register-root=c:\mytexmf

If your still having problems, on a portable install that setting may be stored in a single miktexstartup.ini file, check its contents and there is not a second file with that name. In a basic user install it is stored in the registry under Computer\HKCU\Software\MiKTeX.org\MiKTeX\2.9\Core. If your confident with searching you could check the entry is identical.

To test it works download a well tested additional package such as mwe.tds.zip and install that (unzip the contents so included folders doc source and tex are included in your personal texmf as mytexmf/tex/ mytexmf/doc mytexmf/source)

Ensure you Update file name database either in console or via command line

Prepare a simple MWE file

\documentclass{article}
\usepackage{mwe}
\begin{document}
\blindtext
\begin{figure}
\includegraphics[width=.48\linewidth ]{example-image-a}
\includegraphics[width=.48\linewidth ]{example-image-b}
\caption{MWE to demonstrate how to place to images side-by-side }
\end{figure}
\blindtext
\end{document}

it should run and you will see a reference to C:/mytexmf\tex\latex\mwe\mwe.sty thus proving the personal texmf is set correctly for a .sty NOTE: MiKTeX uses / for the stored absolute part to texmf and \ for the relative parts below that, this is acceptable to windows.