One thing I can tell you from a repair standpoint I've discovered over the years, and
 that is when a computer's IE doesn't work right (IE6-->IE11); then there's usually serious windows corruption, registry corruption, or damage due to a virus that's lurking in your system or from removing a virus from your system improperly.
Nowhere in your posts in this addressed, or so you say, by attempting to perform virus scan and removal.  We normally suggest that you first use whatever built-in AV program you are currently running on the computer in question.  Scan/remove all viruses found.  Next, visit 
malwarebytes.org and download the best free antispyware program 
MALWAREBYTES, and scan/remove all found spyware viruses.  Reboot the computer and re-test your IE11.  If it suddenly begins to work; the source of your problem was a virus and your now good to go!
  You should know that with spyware viruses, they most commonly do these 3 things:
1.)  Attack windows system files that remove mobile devices (laptops/tablets/smartphones) from using the Internet.
2.)  Attack Wi-Fi drivers or wired Ethernet drivers on your PC or mobile device which keeps you from using the Internet.
3.)  Attack IE11 or actually 
ALL versions of IE going back to IE6.  This typically causes IExx any version from working on the Internet, and or breaks IE functionality such as Home Page Hijacking occurrence.
You may think that of course you checked for viruses on your computer?  But, how thoroughly did you really check? Did you remember to check for Rootkits and Bootkits, commonly used by spyware viruses to inject Ransomware viruses into your computer into various system partitions?  On some W10 computers, there can be as many as 11 hidden system partitions where these viruses can hide.  Did you check all of them?
If not, you should use tools such as 
Norton SafeScan online scanner or 
TrendMicro RootKitBuster available at 
trendmicro.com
If you do a more thorough check and still don't fix your IE11, most likely the virus(s) are too entrenched or did too much damage to repair it manually or using software tools.  You'll have to use more Advanced repair methods such as 
Windows Reset or complete 
Windows Reinstallation from Factory Recovery Media after a complete drive erasure.
 [MAKE SURE TO BACKUP ALL YOUR PERSONAL DATA FILES TO EXTERNAL MEDIA, AS MORE AGGRESSIVE SOFTWARE REPAIRS CAN OFTEN LEAD TO IRRETRIEVABLE DATA LOSS!!!]
Bottom line:  If you can't repair your IE11 by any of the above methods, you'll have to reset or reinstall W10 completely to fix it, assuming that your hardware has been tested (RAM sticks and Hard Drive) as Ok.  My Troubleshooting Guide will provide you with Hardware Testing steps if you wind up getting this far to fix your problem.  Guide is here: 
Windows 10 - Unclickable Task Bar
Best of luck,
<<<<BIGBEARJEDI>>>>