The quality is definitly on the better side but the brand has the same ethical issues as H&M and others. There are other 'basic' brands like ASKET that may be a bit more expensive, but don't have these problems in their supply chain.
How are you sure? ASKET has a factory not that far from were I live. I can't find the factory anywhere on the map but looking at some of the provided photos, they don't have air-conditioners. This place becomes boiling hot in the summer. I can't affirm for 100% certainty that they are a shitty workplace but I'll bet $100 that they are as shitty as the rest of textile factories here.