Have a 2013 Toyota Camry with 68,000 miles. The first 9 years of owning the car, only changed the oil once a year (6K to 9K miles per OCI). I've since learned better, and started changing it every 5K miles or 6 months. It runs fine. Not burning oil. Oil filler cap is clean, and don't see sludge when I've changed the oil. But wondering whether it makes sense to flush the engine to clean it out, especially for any piston ring deposits, for any thing that might have built up before I started taking better care of it. It's a 2AR-FE, so it's prone to becoming an oil burner, and trying to do what I should to keep it from getting to that point.
Maybe try the carbon clean product that Scotty has talked about quite a bit in his videos.
https://www.atscarbonclean.com/
I've only seen Scotty recommend the ATS engine flush/cleaner. Won't hurt anything, when done properly, and it can definitely help clean out carbon deposits. Go for it, I would.
