Paying off mortgage (early) vs investing.

Title says it all, some more info: My gf and I pay off 1660 eur per month for our mortgage (400k at 1,85% over 25 years) while earning about 7k monthly on average together (including yearly bonus etc). We are not at the point yet where we can pay off the entire mortgage, however, when we do, would it be better to use our savings to pay off the entire loan or just keep investing? My gf would go for paying off the mortgage for 'ease of mind' and knowing the house is 'ours'. Also , this would free up 1,6k monthly which just feels better on the short term. As financially it makes more sense to me to keep enjoying that 1,85% mortgage as long as possible I would choose to keep on paying the mortgage.

Curious to hear other people's opinions on this and what are (dis)advantages for each situation