To be honest, I think that it is always very difficult to compare because things vary a lot by route and thresholds can also differ a lot across airlines.

One extreme is Air Nostrum (IB subsidiary). On a short lunchtime domestic, all I had was a tiny Haagen Dazs which was pathetic. By contrast, on a dinner flight of under two hours, I had a huge full tray with gazpacho, starter, a choice of two excellent mains (tried them both), cheeses, and dessert not to mention a much better drink selection than CE (except for bubbly fans as you get a mediocre Cava and no Champagne).

Compare to BA - well, on short domestic lunchtime flights, BA is head and shoulders above that Haagen Dazs. By contrast, their dinner offering on a 1h45 flight is frankly paltry compared to that fabulous dinner which was in fact closer to what you'd get in CW (and incidentally much better than IB mainline for the same distance).

LH now. on longer routes, the all day meals are a notch above CE in my view - with a choice of three hot mains (as compared to two hot, the quality of which has somewhat weakened in recent months or a small cold), a much larger starter an additional salad, nice dessert, chocolates, etc. By contrast, on a 1 hour night flight where you'd get a cold dinner on BA CE that would be perfectly fine for such a nice flight, you may well get a vile half sandwich and chemical ice cream on LH.

I disagree with you on similar quality between OS and BA, I find OS quality consistently (and significantly) superior in C and again, you get hot meals on much shorter flights than CE (as you would on TP). AF, TK, and A3 also have consistently higher quality than BA in my view, but KL, SN, and SK consistently lower. TK and A3 are also more generous, and I really love TK's multiple starters whilst OS and AF are broadly comparable (though more generous on band 4 equivalent flights and OS on short ones). AZ varies from disgusting to wonderful and to this date I have never been able to figure out if there is a system or a logic behind what they offer within Europe - sometimes you get a much nicer meal on a 1hr long NCE-FCO than a 3hr long LHR-FCO at the same time. I have stopped trying to understand. LX are weird as my best guess is that their offerings seem to vary according to competition rather than length or time. On some routes, you get LH-like horror, on others at with the same departure time and a much shorter duration, you get a full hot meal. Go figure.

My sense is that BA is best for the shortest of flights (such as domestics) and good for band 3. In my view, band 2 remains the weakest offering especially for afternoon tea which I still find very poor and brunch which is short but not good (and that's my luck because band 2 is my main distance!) and band 4 is the same as band 3 but on flights that long you get better quality and choice on many other airlines. So in my view, CE is "on par" with the following nuances:

Band 1: Better than most competitors on such distance
Band 2: Weaker than most competitors (except the nasty LH) on such distance
Band 3: Middle of the pack or slightly better
Band 4: A bit below par and less good than a few months ago.