hi matt,
had the same ssd as you are, i managed to install a fresh copy of windows on my ssd with all drivers installed, and i also experienced that slow experience which you faced, this is what i have done to my system hope it helps you.
system protection/advance/performance/visual effects -> adjust for best performance
disable windows update and under microsoft app store/settings/app update -> off
under msconfig/startup -> i disable all
uninstall all the games and apps that i dont use and i end up having a fast machine again.