This forum has ruined my keyboard and monitor plans...

[Roadster Lewis]

Thanks, I guess I can see how I get on with the keyboard that I've already had for 12 years...

Thinking out loud I guess I can keep the third configuration to be paired with the dongle, and only plug that in for the login screen if needed.

 

[Amethyst1]

Most external displays are made for the PC market.

I don't see why that led to the disappearance of ≈24" UHD panels. Sure, using arbitrary (e.g. 150%) scaling on Windows means you don't need super-high PPI to get a sharp image and lots of screen estate but all else being equal, higher PPI always means a sharper image no matter the OS. Presumably demand is substantially higher for 27" and larger UHD panels than for smaller ones so it doesn't make sense to produce them anymore (with one exception).

There was only ever LG AFAIK.

Samsung made a 23.6" UHD panel. Used in:

• Acer EK241QK (presumably - not confirmed)
• AOC U2477PWQ
• Asus MG24UQ
• BenQ BL2420U
• Samsung U24E590D and U24E850R
• Viewsonic VX2475Smhl-4K

LG makes 23.7" - used in:

• LG UltraFine 4K (24MD4KL-B)

- and 23.8" UHD panels. Used in:

• Acer CB241HYK
• Dell UP2414Q (tiled, uses MST) and P2415Q (SST)
• Eizo CG248-4K
• HP Z24s
• LG 24UD58
• NEC EA244UHD
• Philips 241P6VPJKEB

As of recently (November 2021), there's also:

• ElectriQ 24" [mini-review]

Source

Edit - I forgot Eizo also have a 21.6" UHD OLED display - in the same price range as the Asus...

 

[Christopher Kim]

A 27" 4K at HiDPI 2560x1440 looks perfect. No reason not to use this resolution. Yes, it's a "scaled" resolution, but the M1 slices through it without a single stutter.

I'm using a 32" 4K at 3008x1692 and it also looks amazingly sharp and the M1 never drops a single frame.

Ditto 4K scaled to look like 1440p. Looks great. New GPUs should be fine with it.

Another +1 for using a 27" 4K and running at scaled 2560x1440. I've been running this setup off my 2016 13" MBP for almost 5 years now, and it looks great. As other have said, macOS still pixel-doubles this effectively to 5120 x 2880, and then downscales it to fit the 3840 x 2160 4K screen. Honestly, I know a true pixel-doubled 27" 5K for 2560x1440 would be better, but given the lack of 27" 5K screens (and even when you can find the LG Ultrafine), at a fraction of the cost, I think it's a great bang-for-buck value.

As others have mentioned, the other consideration of doing this is that it's more taxing on the GPU for non-integer scaling. But has been fine on my 13" MBP with pretty old Intel Skylake integrated graphics (though admittedly I don't do much graphics-intensive work). If you're going to pair it with a newer M1 MBP (or an M1X 14"/16" MBP), I think shouldn't make a difference.

 

[Roadster Lewis]

Thanks, it seems like this is the way to go, unless something more compelling is announced before I buy.