Also, many flatpak apps are not even official such as Spotify. The snap and .deb version of it is official app but software recommends the flatpak version.
I would really like that too. The default behavior causes so many problems for people switching to Linux. Unfortunately, the order of the displayed package formats can no longer be changed via the dconf editor; or rather, the command doesn't return an error, but it doesn't work.
(at org>gnome>software>packaging-format-preference).
The only solution is to completely remove the plugins for the other package formats like snaps and flatpaks from GNOME Software or to run
flatpak remote-modify flathub --disable
to disable flathub. I found no solution yet to change the sort order to .deb packages at first position.
I removed the gnome-software-plugin-flatpak package (I need to keep snap because some apps still make you deal with adding GPG keys, dearmoring them, messing around with trusted keyrings, manually editing sources.list or dropping files into sources.list.d, updating everything, and hoping nothing breaks… instead of just installing the thing and being done like a normal package manager.)
But even after doing that I still see flatpak as an option.
The problem really exists because Team Zorin named the packages Zorin (APT). So it uses alphabet sorting. If Zorin were removed, APT would be the first option all the time. APT has been around much longer than Team Zorin.
Since March 31st, 1988 to be exact. Literally, the oldest, most trustworthy, and dependable source, to installing/removing software. Flatpack installation might be quicker/easier, but it requires more storage space.