8.9.0 adds the possibility to split a large track into multiple shorter ones. Here is how :
While editing a walk, select a point where you want to split the walk.
Next : tap the three dots at the bottom left of the screen

Tap “Split at selected point”.
You will not see it at this time, but a new walk, containing all points up to the selected one, will created and every point before the selected point (selected point not included) will be removed from the walk.
You can repeat this as many times as you want.
When you are done splitting, you can either cancel – this will keep the selected walk untouched but the final subsection of the walk will not be created – or save the the modified walk. If you save, you’ll have the original walk completely divided in multiple segments. But the original walk will be lost.

If you want to split a walk and keep the original walk, best thing to do is to upload the walk to your private cloud database before splitting.