This one's easy
Ignore each airline's creative measurement, or even your own experience

Empirically each plane type has the same cabin width between airlines.
There's not much airlines can do if they choose to fit in the normal number of seats into each row. Even if there are different width between armrests/different width of armrests, it all just means wider aisles/narrower aisles, which still ultimately comes back to passsenger comfort (how fast the service is and how many times FA knocks your arm)

You can swear one airline's A350 9-abreast seat is more comfortable than another but certainly it won't be borne out by the numbers.

CX considering [confirmed] having 10 seats per row?

I don't believe that confort equates wholly or directly to numbers.
What it does relate directly to is the seat construction and design,cabin temperature air quality and decoration, quality of the entertainment - size and and quality of the screen , crew attitudes, food and drink quality plus availability cleanliness of the bathrooms.

Maybe for premium seats
Not for Economy though. It really can really be reduced to numbers.

Even padding should be reflected in pitch.
As for IFE, this is a diagonal square inch and resolution comparison.

because there are some who have already special meals such as vegetarian etc.

I take your point on seat design. I recall MK seats back in 2010-11 (when I had work on in Mauritius) being not too small, but the seat cushion (i.e. bit you'd sit on) was thin and it felt like sitting on concrete. I also recall the CX Y seats which slid forward so as not to recline: solved one comfort issue but introduced another (but at least had armrests not as narrow as today's)

However, as percysmith says, in the back end much of it does boil down to seats across and pitch between seats. And especially so for me (and I'd guess other long-time MPCs) when it comes to CX. We remember and notice narrowing or loss of pitch. We also note loss of cabin service (e.g. the second drink service which was temporarily halted 20.5 years ago in aftermath of SARS#1 never to return, through to loss of any drink service besides meal, fewer cabin crew around)

And I'd say especially so again for me as an independent consultant who needs to justify flight choices to clients. Previously it was relatively easy to justify paying extra for CX: schedules, reliability, lounge access + in past years meaningful priority for rebooking (and in years when I was gold or the one when I was diamond and they had the guaranteed availability 72/24 hours in advance) that was an easy sell. These days with still butchered schedules yet prices often substantially higher than alternatives, and with any service premium largely eroded (or worse), it's not a sell that's as easy now. Also, I need to believe it's worth it myself - and that's getting harder these days too...