Consensus is that you should prioritize on screen size and picture quality over a specific operating system. All inbuilt versions of official AndroidTV will be hindered by low powered chipsets and all models will soon become abandonware.

Best solution is to choose an external device among the 10-12 official units mentioned here.

When the producer obsolesces the box it is a simple and painless matter to replace it.

Good luck

Philips TVs, all smart models - they are relatively inexpensive, and as an added bonus have the proprietary Ambilight scene background lighting.

I have a bunch of them at my place, and they are nothing short of awesome.

I would avoid built-in solutions due to the poor performance and limited updates. Google are rumoured to be releasing a new Android TV dongle soon (in the form factor of a Chromecast). Wait for that.

Inches are really important for a tv. What's the ideal size for you?

One I can add to the "meh" list is the Hisense H55F series. It runs Android 9 which is nice and it actually is pretty smooth running but it gets laggy when switching apps which points at not enough ram.
The price was right at $200 for a 40" and it's good enough for the family room where it mostly watches netflix and disney+ but I wouldn't make it my main TV.
Our main TV is a several year old Samsung with great picture but awful smart function paired with a Shield TV. The difference in Android TV performance between it and the Hisense is night and day. The difference in picture quality is huge too but the rest of the family doesn't seem to notice.

Get the best screen you can afford, and attach a Shield to it. Smart TVs are trash.

Avoid all Sony TV’s except the 2018 Master Series, X85G, X95G plus 2020 Models all capable of running Android v9.0 Pie.

Those are the ones that have the much better more powerful Mediatek chipset in them for running a snappy Android OS.

Every other Sony uses a dinosaur old, slow MediaTek chipset that is now obsolete and will no longer get OS upgrades going forward.