As soon as I connect to the wi-fi at home, it chooses the 5 GHz band and after about 10-20 seconds it switches back to the 2.4 GHz band. I have looked in the advanced wi-fi settings and couldn't find a way to force the 5 GHz band. With an app which shows signal strengths of access points it appears on the 5 GHz tab and while connected for that brief moment it does work fine.
The frequency of the 5 GHz band and the channel it is on are allowed in the country where I live/the access point is set to and other devices work fine with it. I have bought my phone from a vendor in the country I live, so that should be set correctly as well.
I couldn't find other instances of this happening online, so if anyone here knows how to force wi-fi frequency or why my phone does this, let me know.