I didn't have a VPS with them, but long ago I had a couple domains through them. One of them had an issue with the auto-renewal and I never got a notification of any kind, only finding out when they had taken ownership of the domain, advertising it for sale. Then they wanted some way, way higher amount of money for me to buy it back. So, I don't have any domains with them any more.
This was years and years ago though, so they might be better now.
This exact thing happened to one of my clients. And it sucked because they didn't even register the domains with Ionos, they registered them with some other company that then got bought by Ionos. They were not technically savvy and didn't understand what was happening until it was way too late. They lost about 8 domains closely associated with their business and with their CEO's research.