If you've been living with the VT60 for years, the OLED won't be any worse than that in terms of image retention so unless you're doing a lot of console gaming it doesn't seem like it should be a big issue. I've had a B6 for several years now and increasingly have been using it with an Apple TV in the last year. I don't do gaming on it, though.Another possibility for LED-LCD sets is the new Vizio P Series "Quantum X" which has been getting great reviews, recently in Sound & Vision and Widescreen Review. Might be worth taking a look.
My wife is pretty bad about leaving our LG B6 on a paused screen sometimes and walking away for a few hours. Most of the time that will eventually result in a screensaver of some sort after a while, though. But I haven't noticed a hint of IR from any of that or Apple TV menus etc. Like you said, LG has kept improving this in subsequent generations, but it's certainly enough of a potential concern that a broad spectrum of feedback is warranted.
Yeah I have our Comcast box and ATV set to go to screensaver after 5 minutes. Hmm this is going to be tough. That Sony X900H is getting some really good reviews as well for an LCD panel, and it's $1000 cheaper in the same size. That's tempting just because I need to replace my Sony X800 UHD player in order to get something with Dolby Vision capability and $1000 would definitely help with that.
I've been looking at a TV for our den, which we hardly use at all, but I have an old 50" Vizio Plama in there that's 14 or 15 years old (and still works like a champ except for banding issues due to the cheap processor in the TV). Anyway, I've been really wanting a OLED but just can't seem to get one due to the price of the 65". The Vizio P series Quantum X is under $1000 and I'm not sure a OLED is 2-2.5X better (the Vizio is a better value for sure). Then throw in a TCL 6 series and the decision gets even harder (if you can even find one). Needless to say, I haven't jumped at buying anything because I keep going back and forth.
As long as they fit in, you shouldn't have any worse effect that what you have now. Given their spacing, your imaging is somewhat compromised currently (this matters more to some than others). I'd get the biggest display I could afford and put it in there
When shopping for a TV, I use this site. https://www.rtings.com/tv/reviewsI wanted an OLED, but my family room just has way too much ambient light, so it did not make sense to go OLED. I ended up buying a 75" Samsung Q80 a while back. Very happy with its performance.