Modern nVidia and rather basic performance.

So... I have a goal: to be off winblows before the support for 10 times
out.  That's a little less than a year.  I had a FreeBSD desktop up to 2005
or so, and would like to return.  In all other spheres, I use FreeBSD.  I
like ZFS.  Etc.
The remaining blocking issue is X11-related.  I'm not even looking (at the
moment) for Steam --- I have a Stemdeck.  I might boot linux for Steam.
I'd rather not, tho.
Here's the first meat of the issue.  I'm using the nvidia driver.  My
display hardware is a 3080Ti.  Things seem to work fine except ... say I
have a large window scrolling a compile.  Then when I click on the kde
button to show my docked things --- the window pasues for seconds ... until
the kde display pops up.
Is this KDE's fault?  Is this FreeBSD's fault?