I've looked into a few of the studies you mention a while back because of personal interest.

Most of the conclusions of large scale studies are not very solid and can often be dismissed with correlation is not causation. Your point is valid, but also very often popular health habits align with the view of what a healthy diet is in society. Therefore lower meat intake often is connected to more exercise, more sleep etc. Of course they often try to correct for it, but it still makes many of the conclusions debatable.

There is however one association that seems to hold up for red meat, whether that's a steak or a shitty burger, which is the connection between heme iron and certain form of cancers:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3261306/#:~:tex....

But at the same time the effect is still very small and not well understood.