Current graph Axe options allow only:

• "Calculated", choosing "random" Axe ranges in each graph,
• "Fixed", forcing me to include unlikely values like -10V or risk line exitting graphs.

I see need for one of:

• "Flexible" option where graph uses fixed value, but expands if data needs it - can work like "Auto-expand" checkbox in UI. This way graphs stay consistent on dashboard in normal conditions, but individual graphs expand if their data need it.
• "Range" option where graph works like calculated, but then restricts value to set range - can work in UI by filling allowed range instead of one value.

Both these would allow dashboard Y-axes to be synchronized in normal situation but also allow graphs to show unusual values if they happen.
Complex alternative would be sharing calculated ranges between graphs on dashboard.