In present circumstances, I would pick option 2.
It sounds like you don't have any other pressing need for cash, so consider using the €10,700 cashback as a lump sum payment on your mortgage. The break fee is likely to be zero or close to it because very little time will have passed since drawdown. This will save you roughly another €470 per annum for two years. So, your €10,700 figure for the purposes of comparing options 1 and 2 should be closer to 10,700+940=€11,640.
I think the extra interest paid in Option 2 over the two years is closer to ((0.044-0.037)*535000*2)=€7,500, rather than €5,184. But my sums might be out.
To pick Option 1, you either need to be unusually pessimistic about where interest rates will be in 2 years' time or really value the extra certainty in years 3 and 4. Would you pay (11,640-7,500)=€4,140 to be sure? If not, take Option 2.