Gaming for 6 hours plus per day depends if you're playing the same game over and over again, and it has a static element or a bright element that comes in the mostly same place, such as rocket league. Expect burn-in to happen at 6,000 hours or so if you're playing the same game at medium brightness. Maximum will burn it out faster; 2000-3000 hours.
What kind of games do you play? Any game that you expect to cross 6,000 hours in 5 years?
Tatatsky logo will definitely burn-in after 2-3 years if you watch it for 5-6 hours everyday. Like I said above, calculate number of days before the logo hits 6,000 hours at medium brightness. 4 hours means 1,500 days. That's about 4 years. 5 hours however cut it to 3 years or so. 6 will be somewhere between 2-3.
Whether someone has gotten burn-in from the dth logos, C7 owners will have to report. Even most C8 ones wouldn't have crossed enough viewing time to cause burn-in. Maybe by the end of this year some users might come in with burn-in reports. Depends on viewing habits and OLED light seting really.
The TV does have logo luminance btw. It does work well in dimming logos. I haven't taken that into account in the 6,000 hours calculation as I'm giving you a conservative estimate. If you do want the best PQ and are ready to take a chance that maybe after 3-4 years dth logo would have burned in, go for the OLED.
If you do, and even if burn-in happens, maybe you can keep that TV after 3-4 years as the sole dth TV and then get a new one at that time. Of course, this depends on your disposable income and how soon you get the upgrade itch.