OpenMandriva Rock/ROME for servers is a fully independent and flexible Linux distribution, installable with only the necessary programs for starting a server environment (eg: no GUI, no desktop apps, but you can of course add them later)

It can run on bare metal as well as inside containers and VMs, such as OpenStack, Docker, or OCI

It supports AArch64, x86, and znver1 (specially optimized x86 build for Ryzen/EPYC processors) and scales from a Raspberry Pi all the way to a 160-core Ampere server

It uses rpm and dnf or zypper for package management and is under the control of the community, not any single company that puts its own interests above the needs of its users

It also provides easy-to-install workloads, including a mail server with Webmail, IMAP, SMTP, DKIM support, SPAM and virus filtering, shared calendars, and more

OpenMandriva is "stable" but not "stale" and offers the latest technologies and features in virtualization, programming languages, and server software

Bonus:
OpenMandriva is the continuation of Mandrake Linux/Mandriva Linux, which dates back to 1998, and it is one of the oldest still active Linux distributions