Hi Daniele, I called support and finally someone suggested to split the 2.4 and 5 Ghz networks… which did solve the VPN and speed issues. I now have two SSIDs available.
I have devices that only support 2.4 Ghz (Chromecast) and the Connect Giga Box really struggles with that.
I could now complicate your life by demanding another bug free modem, but for the moment the new operating mode is fine. 😉
It’s just very sad that support only came up with this solution for me after 3 months and numerous calls, after exchanging the modem twice.
I talked to very incompetent support people (sometimes kind, sometimes not so much) who mixed up customer data, one lady even blamed my skills suggesting to involve more computer savvy friends/family on my behalf.
Except from Michael no one took the steps to look at the issue step by step and from multiple angles.
Thanks for the prompt answer here in the forum nevertheless.