I'm not a gamer at all, my only game is HMM 3.5 which was downloaded 15 years ago. About a year ago I had to leave my hometown because of the war UA - RU. I'm the only user of my laptop and no one else can access it in the apartment - there's no one but the cat who doesn't like BTC at all. During this time, nothing strange or dangerous happened to the software. The license is irrelevant to the situation as it doesn't require cracks or anything like that. So I really don't have any options how it could be other than if the seed was stolen much earlier, more than a year or three years. But judging by what happened, one gets the impression not of long-term storage and use years after the theft, but that the penetration took place in a recent period, which is impossible in my case.
A few years ago there were some malicious Electrum servers broadcasting a message to Electrum users directing them to download and install a malware version of Electrum. The malware wallet would send all the bitcoin in the wallet to the hacker's address whenever the user made an attempt to send ay transaction. I don't know if seed phrases were compromised by the same hack, but that certainly could have happened.
I would suggest you start from scratch; fresh OS install, fresh Electrum install and make sure to [url-https://bitcointalk.org/index.php?topic=5240594.msg54223763#msg54223763]verify the download[/url] before installing it, and then create a new seed. Write the seed down on paper, and store it in a safe place. Don't store the seed digitally, and don't store on any cloud servers.
Here's a guide for verifying Electrum with GPG:
https://bitcointalk.org/index.php?topic=5240594.msg54223763#msg54223763