Hosting providers do the management of Nextcloud for you (install/updates), hosting environments are still different. I know we have tagged a few of them with hosting.
The big issue with webhosting is, that users often have little experience. Setups on hosted environments are be much more difficult (and in some cases nearly impossible) because you have less tools available to analyze the problem and for each hoster this can be a bit different. Since you already need larger hosting packages, vservers or small dedicated servers are in a similar price range and allow much better controls.
We have used a few tags in the past, like ionos in your case. Not sure how much we should invest in this, it takes a lot of time, and often it is a dead end because the hosting system is a black box. However, in the end, they say how unreliable Nextcloud is…
This will guide you through what we can and cannot support on this forum.
It is not a category issue, only an issue when it relates to our actual support and basic discussion.
Everything else is between you and your shared hosting provider.
Cheers.