See your running balance against upcoming bills.
Insights → 90-day forecast. Income bars above zero, bill bars below, running balance line. Red band over any projected shortfall.
Recurring income (Settings → Income) plus every active bill's next occurrence over the next 90 days. The starting balance is your current balance (manually entered, since we don't connect to banks).
If the running balance dips below zero on any day in the next 90, that range is highlighted red. Click the band to see exactly which bills push you under.