Devs need to write the 1% of automated tests needed just to prove that what they wrote works in the ideal case. QA is valuable for writing the 99% of automated tests that prove that the software works in the edge cases, with DevOps occasionally dropping in to make sure that the test suite runs quickly.

The way you solve Product and QA being at odds is very simple: QA loses, until they don't. When trying to find product-market-fit, it doesn't make sense to delay delivery to prove that an experiment works in exceptional circumstances. Eventually you do have product-market-fit, and you want to harden the features you already shipped, which is where QA comes in - better internal QA finds the bugs rather than your (future) customers. Eventually you start launching features to a massive audience on day 1, and you need QA to reduce reputational risk before you ship. The right time for QA to intercede and get a veto on delivery changes over the lifetime of the product, and part of whether or not QA is a net-add is whether your organization (leadership) is flexible enough to accept and implement that flexibility.