I mentioned above that I have Steinberg and Waves on my "never again" list. I forgot to add two others, Slate and iZotope.
I've purchased 2 iZotope products over the years. Both had problems being correctly scanned by a couple of plugin scanners. Sometimes they scanned, and sometimes not. Too unreliable. Uninstalled both.
When I was first getting started with "in the box" recording and mixing, I bought some Slate plugins. They only supported licensing via the iLok dongle and not soft licensing to my PC. Sometimes my desktop got along OK with the dongle, other times not. When iLok cloud licensing came out, they updated those plugins to support the cloud, but didn't add machine licensing at the same time. Over about 10 years, they never once responded to any of my attempts to contact them. When I moved to France, I sold my desktop PC and bought a high-end Lenovo laptop. It has never once recognized the iLok dongle, so I can't even deauthorize the Slate plugins that are on it.
As I also mentioned, I have a license for Komplete 9 that I've never upgraded. Successive releases just looked like bloatware to me. Komplete 15 seems no different. Hard pass.