Larian Studios Forums Baldur's Gate III Baldur's Gate III - Help Tips & Tricks Stats increases from items, how does it work?

No these things generally don't stack.

The difference between the gloves and the armour is this:

The gloves raise the DEX to 20 - so as you discovered if your DEX is only 8 it will bump to 20.
The armour only raises DEX by 2 - so your 8 DEX would have only gone up to 10. The '20' part is the max - so if your DEX was naturally 20 (without any equipment) the armour would not raise it any further.