Question about secure boot

I came back to The Finals after a few weeks.
And I found that the game suddenly ask me to turn on secure boot, only for my main account that used only system the finals before
Maybe my main has been flagged by player reports, but perhaps they couldn't find cheat evidence?
Can they do something with secure boot?

What exactly is your question? If they can ban you because you had secure boot turned off? No. Every normal windows user can turn that off. Just turn it back on and enjoy the game ;)