My parents are getting a new tv, and are asking for recommendation. I think all I can influence is the brand/model (not realistic to propose rpi and more complex systems). I instinctively avoid google/android and lean towards anything else open source, so probably LG WebOS… But I had bad luck searching for more detailed comparisons. Maybe you have experience or opinions?
LG is currently even worse than Android - it autoinstalls (gambling!) Apps(yes,we made sure there was no hack/malware), tries really hard to get into the network, etc. But I might be biased as I am very unhappy with their support as well - their display showed a faulty line exactly 10d after the guarantee/warranty ran out, they quoted more than the current retail value for the repair and 80% of the original retail value. For a problem that is very likely not even the display itself but a faulty cable. Fuck them.
Personally, if a Pi is out of the scope (which I totally understand) I would go with a Android box and any TV you like displaywise- while Android is as bad privacy wise as any other TV OS nowadays, it is usually far easier to lock it down at least partially so at least the worst problems can be avoided/most of them can be rooted or get linage OS installed. Just make sure the box you use can do that.
Because in the end it’s also an usability problem - your parents will call you if Netflix, Disney+ or something like that refuses to play because they now require widevine in a newer version than LibreELEC offers,etc. If you want to support that, go for a Pi. If you don’t, find a middle ground.