Since i didn't find the guide anywhere when i searched for it when troubleshooting i just post it here so it might help anybody else who wants to play some SMACX and Gameranger isn't working.

This guide will only help after the initial setup for Hamachi and if you still can't find your friends games.

It worked for me and my friend on Windows 10 with the GoG-Version of Alpha Centauri.

1. Go to network adapters and right click on Hamachi->Properties
https://ibb.co/r4PBxNH

2. Select IPv4->Properties
https://ibb.co/GPwLt2w

3.Click on advanced
https://ibb.co/HzQHZ9n

4. Click in the text bar next to interface metric? and replace whatever number (probably 9000) there is with a 10. Remove the check on automatic metric if neccessary.
Then remove the preset Gateway and add a custom one yourself (arrow 1.)
https://ibb.co/kMvxLgZ

5. Set the Gateway as shown in the picture (5.0.0.1) and the metric to 1500.(again no automatic metric)
https://ibb.co/KNwChrg

That did the trick for us. we can finally play over Internet. Oh and this fix also works for some other games aswell. Like Anno for example. I hope this helps anybody.