Pleasure, To note is that the mibox is only wifi connection by default, but most who want to go with ethernet lan connection uses a 3port hub with built in Lan port with no problems( Orico is the brand I use and got from takealot, is mentioned on firts post). I believe your AP will work as it's of knwon trusted brand as well, this box does 2.4ghz and 5ghz, but 5ghz is suggested by most-mine did connect well on a 2.4ghz tplink that was a room away( I do prefer hardwired and is how I now run). There was firmware issues regarding Wifi before Android 8.1, but when I got my box it was already updated to 8.1 with no issues experienced and outperformed my Minix U1 in media playback..no stuttering on all 4k files including 4k HDR, Dolby Vision etc at 30-60FPS(formats avi,mkv,ts,mp4 etc all tested). I pesonally love the Mibox S(google certified and there is only a few of those), but the Ematic is also good bang for buck and the cream is the Nvidia Shield(awesome hardware,but pricey)
Regarding your initial problem, it would be great if your Smart Tv let you access app and let it clear cache etc like on android, is there way to uninstall and reinstall to see if it fixes it to save some bucks before buying?(just to note I received my 55inch Lg 4k smart tv and still testing it and can say thus far,awesome visuals,but not smarter than my mibox regarding apps and usability). Hope it helps and you get sorted because last thing what you need with entertainment is hassle,it's your relaxing time and not getting aggravated time,that I leave for work,lol