At the time I stood my server up, I was supporting RHEL at work and support for docker seemed a bit spotty. IIRC, it took both setting up the docker yum repo directly, along with the EPEL repo. And every once in a while, you could end up in dependency hell from something which was at different versions between EPEL and the official repos. Ubuntu, on the other hand, had better docker support in the official repos and docker seemed more targeted at .deb distributions. So, I made the choice to go Ubuntu.
I suspect this is long since all sorted. But, I see no compelling reason to change distributions now. The base OS is solid and almost everything the server does is containerized anyway. If I were to rebuild it, I would probably use something more targeted at containerization/virtualization, like Proxmox.