I've read that 43" TVs are often rather poor, but that's the biggest size that will fit. I am in Europe and the budget is around €400, and Amazon would be easiest.

I have never actually used a smart TV, and I'm wary, but after, err, several months of pondering, and still not knowing how to actually try a few TVs and see what their operating systems are like... I think I have my mind on buying an Android TV, since at least I already know Android a decent amount, and I've read that most of those TVs do allow ADB access for things like replacing the terrible, spammy launchers they generally ship with one of your choice, or sideloading the apps you want, or disabling pre-installed apps that you don't want as you consider them spyware or anything.

But... while it's great that "most Android TVs" allow this stuff, which ones actually do? What is a decent brand (or even specific models, that would be lovely!) that keeps their Android clean and up-to-date but doesn't mess too much which it and with what the user is allowed to do, without removing options or locking them out?

I've even learned that there are a couple of Hisense TV models with an unlockable bootloader (no exploits, just standard fastboot), which would be ideal, but then nobody has made an alternative ROM for them, so while that's great in theory, I'm unsure it currently helps me in practice.

A bit of an open-ended question, because I'm really not fully aware of the details having never used one of these TVs, so please let me know of any detail that you think a clueless user of older "dumb" TVs might know nothing about, despite most of you here seeing it as obvious.

For example, do TVs these days tend to come with a competent remote control based on, say, BLE, given all the smart stuff they are meant to be doing, or should I still expect just infrared? Will they allow me to connect Bluetooth audio devices like any Android phone would? How is reception of regular broadcast (DVB-T2 here) TV implemented, is it an app, or does it feel more like a regular TV by default and then you can go into the "smart" app-y section?