What TVs are as good as S20+ display?

The Samsung phones use an OLED display, which would explain why you like watching from your phone. A $400 Samsung LED couldn’t hold a candle to an OLED display.

I have two OLED TVs in my apartment, and I never want to watch something on my phone because my TV is a million times better.

When will the official churches start praying for the false prophet? Orthodox Christian three hand signs are different than Buddhist mudras. Ecumenism = 263 heresies; each heresy leads to hell. Orthodoxy = the only true faith; Roman Catholics tried one cup - one spoon ritual and got sick with Bubonic plague; if heresy enters Orthodox monastery then monks/nuns will get sick with flu/tuberculosis (for instance); Orthodox churches who closed for COVID or had disposable cups/spoons or dipped spoon into alcohol are no longer brides of Christ (now they serve Satan and honor Satan's new COVID religion). Don’t go into UFO to be “healed” by evil demons; demons never do good. SSN is written as a barcode/QRcode; then it's put into a chip; chip is put into vaccine; chipped people are influenced (by super computers) to receive grey plastic card World Passport with no name on it (but when they stretch their hands to get it, gov't clerk presses secret button to administer the unforgivable green 666 tattoo by isotope rays). If you reject mark of the beast (by hiding within a 10-15 people group according to saints Gabriel Urgebadze and Seraphim of Sarov), then your direct ancestors go to heaven (according to saint Vyacheslav Krasheninnikov from Ural); forgive me.

One major reason that they look so good is because you’re watching hi-def content on a very small screen (compared to *any* regular TV display).

At that size, slightly soft images look sharp simply because they’re below the threshold of what you can see. 

Your small screen phone is also capable of varying the brightness of almost every pixel; most TV displays cannot do that and instead rely upon a single backlight for the entire screen. If you want to recreate that then either an OLED screen TV or a far cheaper non-OLED model is capable of that if it has “local dimming”. The latter feature does not alter brightness for individual pixels but for groups of pixels instead and the effect is good enough almost all of the time. 

Strictly speaking, a 40” screen when seen at normal viewing distances is too small for the vast majority of people to see the difference between regular 1080HD and 4K.  That difference is not usually noticeable until you get to around a 56” screen. But if you’re a “pixel peeper” or sit closer then you may well see the benefit of a 4K screen. I’m unaware of any 8K screens at 40” but pixel peeper or not you certainly wouldn’t see the benefit of that over 4K at just 40” or even at 56”. Not least because 8K isn’t that much better than 4K: to double the linear detail resolution would need 16K.

So just look for a 4K OLED or a 4K local dimming LED model. Note that OLED screens still have a much shorter predicted lifespan than LED screens, and on some ex-display and new-ish secondhand OLED TVs the colour gamut is already noticeably less vibrant than when they were new. But that fault is not considered to be screen failure.

One of the biggest differences between cheaper TVs and decent brand name models is the quality and design of the remote control and the TV operating system. Last year I bought an LG model for my wife: the screen and sound quality are outstandingly good. But the LG OS is simply awful as is the design of the standard remote and also the expensive upgrade alternative LG “Magic Remote”. Not really a problem for us now that we’ve adjusted the TV settings to what we prefer as we only use that TV with an Amazon Fire 4K TV Stick. 

You'd need an OLED TV.  Minimum of £1200.