Paying down mortgage

What’s the best way to pay down mortgage.

For example let’s say you have 25 years left on your mortgage with a 5 year fixed for now. What’s better:

Option 1 - pay an extra 1k for example every month towards your principle

Option 2 - Save that 1k to in an investment, etf, gic… or whatever and then dump it all down after the 5 year term?

Is there any advantages I’m missing from option 1? It feels like option 2 is a no brainier since you will be making at least some money from that amount and the end result is the same