Talked to my wife. She tried to install a voice changer software yesterday from a link on twitter and it didn't install. This is a windows 11 PC. I see something new called WingFtpServer as a startup program. That has to be it. C'est la vie 
windows 11 has updated security but there are unknown kind of malicious/ pc virus that windows defender fail to defend yet. As you said, she was trying to install a voice changer software, clicking Twitter links, might be the reason. Although software didn't install but may be virus get downloaded to your device & get installed that time. But after that, there are so many step to crack for hack your 11 btc. Core wallets are protected by a password, hard to get crack only if you use weak password. But chance is less here. But i suggest, use a freash device , not for fault useage but only for store your cryptocurrencies, otherwise i found many users experienced such hacking incidents No operating system is completely safe and immune to hackers and viruses whether it is linux or macOS...the safety of computers depends on how we use them.
This is completely the OP's fault, not the wife's fault. He owns a large amount of bitcoin but he does not store it on a hardware wallet or offline device. He used a device with an online connection to store bitcoins, which was a big mistake. Meanwhile OP is not a newbie and he also understands the risks of storing bitcoins on regular online devices. This really makes me doubt what the OP is saying.