In 2025, the package manager and frequency of updates are the only real differences between most distributions. I’ve been enjoying Flatpak for years now and hope it continues to build momentum. It offers the possibility of shared effort between distributions who depend on legions of volunteers constantly updating debs/rpms/whatever.
It feels like one of the last hurdles to eliminate so much of the duplicated effort associated with all these distributions.
Patience. Same things will work differently than you’re used to, and that can be frustrating.
Also be really sure to help true beginners understand software centers and package managers. I’ve been helping a lot of young people use Linux for the first time this year. Even though I mentioned it the first day and remind them frequently, if for example I ask them to install Java, half of them will download installers from Oracle’s website or wherever.