For your old consoles, the best connection is generally RGB scart. My man-cave TV is five years old, a Logik TV from Currys (own brand) is 24" 1080p* and has proper scart, composite and component connectors and doesn't have any input lag. The image quality is fine and very similar over SCART and Component, and the aspect ratio can be adjusted to 4:3. In my opinion it looks as good as I remember our old Sony CRT TV being. I certainly have no desire to hunt down a giant CRT TV for old console games. Our main TV is also a good five years old and has weird 3.5mm input connectors for "AV". It came with adapters for SCART, Component and Composite and I can only do one of these at a time. It has pretty bad input lag even with "game mode" on.
I might consider hunting down a Standard definition LCD flat panel TV though.
I do most of my retro gaming on my desk. When I bought my monitor I made sure it had a VGA connector. It is now 2 years old and was about £200 so not a top end model by far! 27" IPS 1080p by AOC.
I use this monitor just fine for my Dreamcast, Win 98 PC (1999) and DOS PC (1992), all over native VGA. I set the aspect ratio to 4:3 so it isn't stretched but tbh all cards I tested worked at 1920 * 1080 on the desktop in Windows 98 which is useful! It works just fine in DOS and the BIOS, 320*240, 640*480 etc. I've never had any issues at all with getting a display even when the lower resolutions default to 75Hz. Retro gaming on original hardware is already a time and space consuming faff so I like to keep it simple and not have a bigass CRT on my desk! Plus I am not nostalgic about CRTs. They're hot, flickery, heavy and need the image adjusted to fit the screen. LED screens are better for my typical retro gamer uses.
Also important - what speakers you are using!
* I don't get how my basic TV from Currys five years ago was 1080p, included a DVD drive, freeview and cost £150, yet today the
cheapo TVs are only 720p!? And you can spend
£250 on a 32" TV with HDR... in 720p!