The input bug does make it seem sluggish.
Trust me, try the synaptic driver. See if it helps.
I was about to format the machine but it solved the issue for me.
It caused a log message 'spurious interrupt' or something similar... it hangs the mouse for a few seconds to minutes... i'm not quite sure what the exact bug details are but it affected my dell laptop touchpad. Specifically in linux mint 20.