Eu tenho o mesmo problema, você pode diminuir a velocidade do ponteiro copiando e colando isso em um terminal
xset m 3/2 5
Como funciona
de man xset
mouse The m option controls the mouse parameters; it may be abbreviated to 'm'. Of course, it applies to most pointing devices, not just
mice. The parameters for the pointing device are 'acceleration' and 'threshold'. The acceleration can be specified as an integer,
or as a simple fraction. Threshold is just an integer. The setting is applied to all connected pointing devices. xinput(1) should
be used if you need device-specific settings.