How to turn off Organize by Conversations in Apple Mail for good

Would like to turn off Organize by Conversations for good, as the emails what are in conversation do not appear in correct place and time. Almost got into a big trouble because of that... It's not fun then you are accused and you know, that you have sent the information, but send email does not appear in Sent folder...

Why software engineers in Apple thought that was a good idea, I don't know, it's very dumb and bad idea!

After turning off ObC, emails appear where they should be located - at the correct place and time.

But anyway, the problem is that Organize by Conversation keep turning itself back on. And it happens just randomly. There is no correlation - just randomly. You can have even restarted the Mac and ObC is turned off, but then, after some time, it's just back on. And turning this off tens of times per day is not fun or acceptable.