iPad mini 4 - strange wifi issues

[redtape]

Hi. I will try to be brief. I have an iPad mini 4 128gb with sim card tray / 3g.

Here are the errors:

• Wifi keeps disappearing. Not loosing signal strength or turning off. I mean the actual icon disappears along with the ability to search for any wifi networks.
• The options app can sometimes freeze up when I´m in there trying to fix the wifi.

Here´s what I tried to do:

• Turning on and off airplane mode. (Sometimes works, but error comes back within an hour or so)
• Turning off and on the ipad. (Sometimes temporarily fixes the problem for while)
• Reseting the network settings. (Again, some times fixes the problem temporarily but it always returns)
• Complete factory reset and backup from previous backup copies on my computer.
• Complete factory reset and deleting everything on the ipad, and no restore from computer (to rule out software issue in backup files).

Nothing works. It keeps loosing the wifi and options app freezes up. But as I stated in the list above, sometimes the wifi works, I can see the icon, it connects to my wifi, and I can surf the web.
The ipad is 1,5 years old and I´ve kept it up to date.

Everything else seems to work fine. What should I do? Sell it for scraps or what? Apple wont fix it for free as its only a one year warranty on it...