I personally use a Raspberry Pi to self-host Nextcloud and anything I need with Docker. ARM SBC aren't the easiest way to go for everyone through.
I saw people mention some good ones (Ubundu & Fedora Server, ClearOS, OpenMediaVault) so I thought I would offer some up that hadn't been mentioned.
1) I try not to suggest paid services but Cloudron is a great server for hosting web-apps that are secure and easy to get up. Way easier than Docker. It runs on top of Ubuntu 20.04 There are fees for running more than one app at any time though.
2) FreedomBox is an open-source alternative to CloudRon but I found the documentation really confusing. The apps aren't as well-known or numerous as Cloudron but it's still a stong choice.
3) NethServer is a good home/small business server based on CentOS/RHEL. It features "mail server and filter, web server, groupware, firewall, web filter, IPS/IDS or VPN server".
4) If you installed Ubuntu or Fedora server you might want to consider Webmin. Webmin has been configured to run on dozens of versions of Linux/Unix. Once it is set up you don't have to alter config files like
/etc/password manually anymore.. there will be a browser interface you can log into with a web browser to make the changes.