Looking to transition from Outlook 2007, BUT...

I've been stubbornly holding out with Outlook 2007 all these years for one simple feature that Microsoft seems to have completely left out of each of these newer versions.  I've tried desperately to find a work-around to it, but keep coming up empty.  This is a key feature for me, and I'm hoping someone here can give me a suitable workaround.  Drag-and-drop email copying/linking into file folders on my hard drive - not to elsewhere within the contained boundaries of Outlook.  

I operate a business with many clients, for each of which I have multiple independent projects.  I've got separate folders (on my hard drive) for each project, broken down also by year - so it's not enough to categorize email by client only.  My preferred method of keeping easily referenced tabs on all of those correspondences is to drag-and-drop all those email into those project folders.  Outlook 2007 lets me do exactly that.  I'm told Outlook 2010 also works that way.  But all subsequent versions (including this most recent update) do not. 

Is there a reasonable workaround to filing copies (or at least active links) on my hard drive with the newest Outlook?  I am willing to look at alternative methods of keeping track of my client emails, but it MUST let me pool them (broken down by project and client) all together - as opposed to simply doing a 'search' from within Outlook every time I need to see old correspondence.

BTW, I am not a Microsoft 365 subscriber.  If 365 allows the drag-and-drop capability I may have to consider going against my nature and pay eternally for something that I previously had unlimited access to after a single purchase.  

Thanks in advance for your suggestions.