That the cost of everything being cheaper is that
we have to buy more of it, creating more waste
Is this true? It's an interesting question and one that's difficult to answer in any objective way.
https://en.wikipedia.org/wiki/Durable_good
Using the economists' definition of "durable goods" I would say that for the most part, quality has improved. Cars last 2-3x longer these days. Computers have been "fast enough" for a while and can last 10+ years. Perhaps professional tools have taken a nosedive but my low-end Ryobi tools last essentially forever with light household weekend usage.
Not a "durable good", but cheap clothing also feels way more reliable. Cheap synthetic or cotton/synthetic blends are now comfortable and breathable (which is a relatively new development) and last pretty much forever.
Some things have gotten anecdotally worse. Everybody says that large household appliances like refrigerators, washers, and dryers have really taken a nosedive in quality and/or repairability. It certainly feels true but, I don't know what the actual numbers might say.
But I don't know, man. Affordable crap from 2023 actually feels better than the affordable crap I remember from 1983 or 1993. It certainly doesn't feel worse.