23mm Road Tyres

Where are you looking? Chain reaction, wiggle & bike24 all showing loads of options.

Not sure about "better", but shown to have lower rolling resistance. Depends on the rims I would guess, given that can influence how wide a tyre is the real world (I've always found conti's run wide, on my rims at least).

There was a recent GCN video which used some fairly dodgy science to show 25mm was best, although very little difference with 28mm and I myself would notice the difference in comfort and grip so go to 28 where I can.

On the other hand I have a frame that could be 10 years old at this stage which I have no intention of getting rid of any time soon, only takes 23s

My old TCR was the same - 25s rubbed the frame! Running 28s on all but one bike now - not sure whether they’re faster but definitely more comfortable at lower pressures.