It is true that such a phone will probably have the A/B partitions. Another factor is where are you getting this number from, and are you using binary or decimal units (or mixing them)?
Let me use my Pixel, which also has this scheme, to illustrate: my phone has "128 GB" of storage. But that's in decimal units. In binary (what a computer really uses) that's 119 GB, because a binary GB (2^30 B) is larger than a decimal one (10^9 B). The /data partition is 110 GB in size, so the system partitions add up to 9 GB (actually just under).
So if your phone really is allocating 14GB that's significantly more than my Pixel. But if your /data partition is 18GB in binary units and you subtracted that from 32GB (decimal) and called the difference the system then you will overestimate the size (in that case your real system allocation would be 11-12 GB). So where you got this figure from does make a difference (though it's still more than my Pixel however you cut it).
On the other hand, Samsung usually allocate more than this and they only have a single set of system partitions (and often allocate more space on higher capacity models of the same phone, which makes no sense at all).