Step 1. Smart tvs are all awful. Buy a normal screen if you can and either the extra on getting something better or buy a raspberry pi, pc, console, hope your phone does screen sharing... anything really. If you only want a service it offers on the box like netflix then OK, they may say they do youtube but don't believe it, especially if you have adblock on your PC/phone. I hope you never have to use one of their web browsers for something real outside of you went into a time machine with your TV and it is the 2006 web again. I don't know why they are all so awful (I have seen electronics people staple android devices onto home phones some 8 years ago so I have no idea why they could not do it here) but it is the case.
The onboard decoder features it comes with are of some more concern but for my remaining sanity I try not to consider what goes for US TV these days. External boxes are still the better way for most things.
Step 2. It might vary with your concerns. Resolution is going to be the big one. Most "TVs" are either 1080p or 4K (which in TV land is 4 1080 screens put together), I don't know if there are any 1080i or 720p only models on the market but do be aware of that.
Refresh rate and latency. Old CRTs had basically none and newer panel technologies have more. For TV and video this matters little. For games this matters more. As well as latency inherent to the tech TVs often have things to polish up the image before you see it and this adds more time from when the image is sent to when the results appear on screen. To that end many TVs will have a direct, game, computer... mode that disables as much of this as possible.
I should also say many have token or basically no support for older video input methods for (from?) games consoles either. To that end people have taken to buying upscalers to have them work on many modern TVs, personally I would just emulate but that is me.
After this your concerns really come into play -- do you need 10 HDMI ports or will 2 do? You can always buy a splitter/switch. Do you care if you can't output audio externally to 3.5mm*? I do, many do not, others still solder something in there to make their own or use a splitter/audio splitter. Do you need displayport, DVI (though you can always buy HDMI<->dvi, give or take some hdcp concerns on older devices), VGA, component? You can look at a specs sheet as well as I.
Do note that many older, and even some newer, TVs might have 4k screens but the version of HDMI (HDMI 1.4) they support means it is limited to 24fps rather than 60. HDMI 2.0 grants 4k60.
*owing to how thin they are most TVs sound awful, to that end you may wish to output to a real amp or soundbar or something. Alternatively your external device may allow for this.
Are you really a graphics type? Many TV decoders offer a slightly more limited colour palette than many a dedicated computer monitor. If you don't know about this you probably don't care. You might well require a computer to check this -- granny smith apple green is not magically going to become pine tree green to your eye and it is all going to be fractional.
Black levels probably rolls up into a conversation about HDR (high dynamic range). HDR is many things to many people but assuming it is direct support for source HDR signals (as opposed to trying to emulate it/create it manually) it is what allows the screen to display the blackest black at one point while simultaneously burning your eyeballs out on the white section. Nice but nothing to trip over for me.
3d. No, don't do it. It has failed again and nobody is really doing anything with it. Get a head mounted display if you care about this sort of thing for games.
Curvy screen? I remember when flat screens for CRT were made. It was a marketing gimmick then and is now the reverse is back again.
So yeah for the most part what resolution do you want, what inputs do you need (with the HDMI2.0 proviso for 4K if you need 60Hz/60fps or similar), do you need audio outputs, try to figure out the latency issues if you are going to use it for games, what size screen do you want, can you view it at all the angles you are going to want to view it from? If you are hanging it from a wall then most TVs are light as you like these days but you may wish to check mounting size lest you end up having to buy a new mount or adapter plate.
To be fair I've no idea if it was updated using ChoidujourNX, but that look like it. I also can't seem to use Daybreak on a SX Core so lol. Also pardon if talking about the switch here makes you uncomfortable