It depends entirely on how much warning you were given.
Check your flightCancellation compensation turns on one thing before anything else: notice. Fourteen days or more before departure and no compensation is due, however annoying the cancellation was. Inside fourteen days, it depends on how quickly the replacement flight got you there.
With seven to thirteen days notice, compensation is due unless the re-routing they offered got you to your destination less than four hours late. With less than seven days notice, compensation is due unless the replacement landed you less than two hours late.
Separately from compensation, you always have a choice the airline will not volunteer: a full refund of the unused ticket, or re-routing to your destination at the earliest opportunity. That choice is yours, not theirs, and a voucher is not a refund unless you agree to one in writing.
The extraordinary circumstances defence still applies. A cancellation caused by weather or ATC pays nothing, while one caused by a technical fault, crew shortage or the airline's own staff strike pays in full.
Compensation is a flat amount set by distance, not by ticket price: €250 up to 1,500 km, €400 for longer flights inside the EU and for 1,500–3,500 km, and €600 beyond 3,500 km. The UK equivalents are £220, £350 and £520.
Distance is measured in a straight line from your original departure airport to your final destination, which on a connecting itinerary often lands you in a higher band than you would expect.
Duty of care is separate from compensation and does not depend on the cause. Once you are delayed two hours or more the airline owes you meals and drinks, two phone calls, and a hotel plus transfers if you are stuck overnight. This applies in bad weather, during ATC strikes, and in every other situation where no compensation is payable.
Airlines frequently provide none of this during major disruption. Buy your own, keep every receipt, and claim the cost back afterwards.
Work out what you are owed