You may just have been unlucky with your IP block having spammers. How were you hosting it - own ISP or another provider?
I have not had deliverability issues for years with my Kimsufi (OVH France) server. While I am confident my server is well configured using best practices, I suspect some of it is also just luck not to be in the same IP block as a spammer.
I was using a colocation hoster in Belgium. They actually moved me to another netblock to test (they were a really nice small company). But the same happened.
I heard Kimsufi is indeed pretty bad as it's so cheap people tend to use it for 'throwaway' purposes. It's basically the white label budget brand of OVH :)
I've had 2 kimsufi email servers and both were fine. It shares the same data centres as OVH so I guess IP ranges are similar. No problems with blacklisting based on anything other than my own misconfiguration so far, and it's been maybe 8 years.
I have not had deliverability issues for years with my Kimsufi (OVH France) server. While I am confident my server is well configured using best practices, I suspect some of it is also just luck not to be in the same IP block as a spammer.