I have been using openSUSE. It's been pretty stable on the laptop. On laptop, I use the Tumbleweed (rolling release) and 15.1 or 15.2 on servers. Give it a try.
I'm also a big fan of opensuse lately especially their tumbleweed microos. it's such a breeze to use transactional-update (automatically) and reboot a fleet with some looking mechanism (even with k8s kured).
suse cured my containerlinux wound. (if suse gets bought by ibm than I will be furious or if they kill microos)
Packages are RPMS, managed with zypper. You may also use dnf but you will miss some of the advanced features provided by dnf (e. g. the concept of patches vs updates), there was a zypper vs dnf thread recently in the openSUSE mailing lists.
It does support flatpaks.
There is no free openSUSE LTS. The LTS is called SUSE Linux Enterprise Server, costs some money (unless you are a developer, in that case you get free subscriptions) and the LTS lasts for a minimum of 13 years.
On the other hand, dnf/yum downloads repos and packages in parallel while zypper still does everything one at a time, which means every kilobyte-sized package takes a second or two each to download, from setting up and tearing down a new TCP connection each time. It's especially annoying in Tumbleweed because rolling distro == lots of tiny packages updates all the time.
Zypper is awesome. The newest version of LEAP is identical to Suse Enterprise, you can convert with a simple script if you decide you want extended support.
The root filesystem uses btrfs, so it's easy to roll back update problems. There is also a newer version that uses a read-only root filesystem and updates are applied to a new snapshot that takes over when you reboot. It's pretty cool.
