

One thing you might notice is that flatpak defaults to “system” installs. Is your root system directory filling up? You probably want to start installing onto --user, as this will put things in /home where they belong and, by default, sandbox permissions away from root (that, too, can be easily changed).
Also, don’t fear mixing different ways of installing. I use AppImage, Flatpak, the default app-get install method, and .deb. FlatPak at this point is the best, because it offers the ease of use of AppImage, but the flexibility and auto-maintenance of apt-get/Software Update. The only problems I’ve encountered were due to me not understanding that it was filling up my root partition by default…
I’ve been running Mint MATE for about 9 years. Love it to death.
MacOS has more than sandboxed… they are basically removing the ability of a user to do anything to their computers. I can’t fix my dad’s imac (I used to fix my own macs), they are impenetrable… They’ve more than “sandboxed” apps, they’re forcing all but previously established powerusers to take their dying overpriced lumps to the Apple store. This, they say, is “good for you.” I loved Apple for 8 or so years. Hate them to death now.
My 9-year-old quad-core running Mint MATE 22 boots up faster than both my dad’s 2-year old iMac and my 6-core PC running Win11. And I can tell you what every process running is doing… bonus.