I think their engineering is pretty good, personally. I travelled a lot with a laptop from 2000 to about 2020, and my windows laptops would always die after 2 years - hinges, cracks in the body, screen cracks and so on. Moving to apple’s laptops in about 2011 meant I got 5 years out of each (air then a pro). I’m now on a second pro, but the old pro is still trucking along.
I’m not going to defend all their decisions, there’s a lot of questionable stuff in there (keyboards, sticking to lightening, mice…). But their hardware, both laptop, mini and pro) has been solid.
You are right about repairability. I think that has never been a key feature for them hence the glue, security screws and other crap. Fortunately there are governments around the world that are pushing for repairability, consistency with usb-c, replaceable batteries and more. So I think all manufacturers will be upping their game now, which is awesome.
All manufacturers reduce cost - supply chain management and manufacturability are the processes to drive that. Apple are really good at the supply chain side, that was Tim Cook’s focus as COO. What I don’t like is that they are able to keep their incredibly high margins (far higher than any other manufacturer) thanks to their software, interoperability and walled garden.