@Nekolone & @Sedgen
Thank you for your replies, guys!
Much appreciated, thank you! 
I’ll go through the thread and gather the information for our network team now. However, I recommend you get in touch with your ISP again and ask them to have another look. The reason for this is that, unfortunately, the issue does not start when it comes to access Blizzard servers but way before that.
Please, have a look here:
Note: Your pathping is missing the second part, the one with the percentages. ^^
As you can see, the hop highlighted (the same for you both) is within your ISP’s network infrastructure - we’ll still collect this data but it’s important that you inform your provider of the issue, so they can run the investigation required on their side as well. This can greatly speed the resolution process. 
This said, thank you both again for the information provided, please don’t hesitate to add here any additional updates on the issue you might have.
Feedback? Blizzard EU - Customer Service Forum Representatives Surveys - Vyraneer