I’m totally spitballing here but I’d have to think that regardless of the fabric/weave, 4oz would have to feel more “airy and breathable” than something more than double its weight.

Here’s hoping

Fabric weight or composition alone are not suitable indicators for breathability. In this instance since I haven't handled or worn the individual trousers and fabrics anything I say would be speculation I'm afraid

These are different fabrics in different weights, material compositions, weaves, and dying methods. Same cut, but all different

It’s hard for us to tell you what to buy when we don’t know what you like. What specifically are you looking for in a pant? Pattern, colour, fit…

“Technically speaking, fatigues are just a broad term that includes baker pants. Although some people would argue a baker pant is specifically a closer reproduction of the original OG-107 utility pant, whereas “fatigues” has become more of a general catch-all term over time.”