I left Red Hat a bit after the IBM acquisition, and in my experience the management bullshittery was encroaching about a year after the deal closed. I hear their sales team are all frustrated and leaving due to IBM’s interference in Red Hat deals.
Contrary to the HN narrative, pretty OK. Not perfect, I have complaints, but most of them aren't related to IBM specifically.
IBM doesn't assert their will upon Red Hat anywhere near as strongly as HN seems to think they do and in particular the whole story about IBM killing CentOS is BS.