Flatpak is now an indispensible part of my linux setup on debian or an older ubuntu LTS:

Running up-to-date desktop apps like synology-drive, prusa slicer, keepassxc, kdenlive or even Steam at the same time without any conflicting dependencies and configurations tainting the distribution. And if you do not want to use it any more, you can simply remove it with little or even no traces left behind. I love the experience to get these -- including updates -- from within discover (KDE) or gnome-software.

And don't mix flatpak with snap. Different technology, I share mixed feelings about snaps.