1. I run an audio video department, I'm aware of the similarities between the different 2017 LG OLEDs. It's the same panel for all five, but different form factors and audio systems.
2. Do you heavily watch News or Sports? Because those also have a lot of static images.
3. Even if you don't heavily play video games on the TV, LG still recommends powering down for a refresh cycle every three hours. Channel logos, TV guides, and even LG's own logo have all been known to burn into OLEDs over time.
I've had another OLED for a few years and yes I do watch a lot of sports. Never had any issues whatsoever. Its a slightly overblown problem imo. Image retention certainly happens in some conditions (news channels are the worst culprits with their rolling news banners), but it 'washes away' on newer OLED's under normal use. Most UK sports channels have a slightly translucent logo or score/time thing now and they do remove during replays etc. which helps.
I even had plasma's in the past (where it was much more of a potential issue) and I didn't even have a problem there either with burn in.