Change easing to Quadtratic.
MODIFY
WalletWasabi.Gui/Controls/LockScreen/SlideLock.xaml
WalletWasabi.Gui/Controls/LockScreen/SlideLock.xaml
<Style Selector="Border.Chev1">
<Style.Animations>
<Animation Duration="0:0:1.5"
- Easing="CubicEaseInOut"
+ Easing="QuarticEaseInOut"
IterationCount="Infinite">
<KeyFrame Cue="0%">
<Setter Property="Opacity" Value="0"/>
<Style.Animations>
<Animation Delay="0:0:0.3"
Duration="0:0:1.5"
- Easing="CubicEaseInOut"
+ Easing="QuarticEaseInOut"
IterationCount="Infinite">
<KeyFrame Cue="0%">
<Setter Property="Opacity" Value="0"/>
<Style.Animations>
<Animation Delay="0:0:0.6"
Duration="0:0:1.5"
- Easing="CubicEaseInOut"
+ Easing="QuarticEaseInOut"
IterationCount="Infinite">
<KeyFrame Cue="0%">
<Setter Property="Opacity" Value="0"/>

Change easing to Quadtratic.