new desktop computer needed

Am not great at this stuff. Computer guy walked off with my tablet so it's me and geek squad for now (but visits will stop within the year).  Geek Squad hasn't been here yet. The criminals outside are high tech geniuses and I am their crime victim. A cop and private eye help me. The creeps re-install everything outside we get rid of. All content in my computer needs to be G rated and ethernet. (they've gotten into ethernet, by the way). wi-fi is disaster. The computer modem is set to ethernet with an exception of the amazon reader, which has a wi-fi address in modem. The internet provider gives us all ARRIS NVG443B modems. all is fine so far and has been for 3 years.I need a new tower as this one isn't Windows 11 (not enough tps, or whatever it is, in tower). (I am aware one can install the tps, but probably not Best Buy). What tower is best for ethernet, that amazon reader, and a new smartphone (bleech to smartphones, love desktop)? Does anyone have any suggestions for dealing with the outside problems which actually include microwave technology? private eye spent six weeks at Langley years ago and is no dummy. Many creeps and actual sent up 7years ago was done by electric utility workers on their weekend, with kudos from their bosses