Owner of an X900F here who has been similarly happy. Great picture with excellent color, contrast, and uniformity that has stayed as good as it was on day one for the past 6 years through probably thousands of hours of usage. (As it turns out, LCD TVs can experience picture degradation as bad or worse than OLED burnin[0])
It’s been perfectly happy to remain totally offline too and is built as if it’s expected to be connected to a streaming box and/or receiver, as opposed to some TVs where the manufacturer really pushes the onboard “smarts” over external sources. Works wonderfully with an Apple TV 4K, PC, and PS5 and can have its firmware updated offline with a thumb drive. Its smart bits are vanilla Google TV though and would be reasonably usable if one were inclined (though I’d advise removing a preinstalled content ID package with a laptop and ADB first).
Also an X900F owner here. TV isn't perfect because we use the "smart" bits of it. I still prefer my old Samsung dumb TV, but it isn't 4k. Overall we're happy with the Sony. Being Android and not updated, it's probably full of security holes. But we have it on its own network and blocking a lot of traffic. UI can also be slow, but after removing and/or disabling a lot of software, it's better than it once was. It plays Netflix and HBO Max great, so we're happy.
Have you updated its firmware? Looks like there’s a new update available as of September 2023, which I haven’t installed yet but I’ve installed a couple before this one.
I haven't. I'm in the "if it ain't broke, don't fix it" camp for TVs. But you've also piqued my interest. I'm curious how much of an improvment it offers, and what features it may or may not have removed.
It’s been perfectly happy to remain totally offline too and is built as if it’s expected to be connected to a streaming box and/or receiver, as opposed to some TVs where the manufacturer really pushes the onboard “smarts” over external sources. Works wonderfully with an Apple TV 4K, PC, and PS5 and can have its firmware updated offline with a thumb drive. Its smart bits are vanilla Google TV though and would be reasonably usable if one were inclined (though I’d advise removing a preinstalled content ID package with a laptop and ADB first).
[0]: https://www.rtings.com/tv/learn/longevity-results-after-10-m...