Are really all these flatpaks unused (except Nvidia latest runtime and a few others)?

Somewhere I found this command for _a flatpak maintenance_:

flatpak uninstall --unused

I did have no free time at that point, so I saved it for later use. Now, when I execute it, I get:

$ flatpak uninstall --unused

These runtimes in installation 'system' are pinned and won't be removed; see flatpak-pin(1):
  runtime/org.freedesktop.Platform.GL.nvidia-535-54-03/x86_64/1.4


        ID                                                       Branch            Op
 1.     org.freedesktop.Platform.GL.default                      1.6               r
 2.     org.freedesktop.Platform.GL.default                      21.08             r
 3.     org.freedesktop.Platform.GL.nvidia-525-105-17            1.4               r
 4.     org.freedesktop.Platform.GL.nvidia-530-41-03             1.4               r
 5.     org.freedesktop.Platform.VAAPI.Intel                     21.08             r
 6.     org.freedesktop.Platform.openh264                        2.0               r
 7.     org.freedesktop.Platform                                 21.08             r
 8.     org.freedesktop.Platform.Locale                          21.08             r
 9.     org.gnome.Platform                                       43                r
10.     org.gnome.Platform.Locale                                43                r
11.     org.freedesktop.Platform.openh264                        2.2.0             r
12.     org.gnome.Sdk                                            3.28              r
13.     org.gnome.Sdk.Locale                                     3.28              r

Proceed with these changes to the system installation? [Y/n]: n

I do not want to cripple my system which is Linux Mint 21.1 Vera Cinnamon. Could anyone tell me how to determine for sure if these flatpaks are really not used? --- The whole list of flatpaks installed in my system follows:

$ flatpak list

Name                                                    Application ID                                           Version               Branch                 Origin             Installation
PyCharm-Community                                       com.jetbrains.PyCharm-Community                          2023.1                stable                 flathub            system
Freedesktop Platform                                    org.freedesktop.Platform                                 21.08.19              21.08                  flathub            system
Freedesktop Platform                                    org.freedesktop.Platform                                 22.08.12.1            22.08                  flathub            system
default                                                 org.freedesktop.Platform.GL.default                                            1.6                    gnome              system
Mesa                                                    org.freedesktop.Platform.GL.default                      21.3.9                21.08                  flathub            system
Mesa                                                    org.freedesktop.Platform.GL.default                      23.1.1                22.08                  flathub            system
Mesa (Extra)                                            org.freedesktop.Platform.GL.default                      23.1.1                22.08-extra            flathub            system
nvidia-525-105-17                                       org.freedesktop.Platform.GL.nvidia-525-105-17                                  1.4                    flathub            system
nvidia-530-41-03                                        org.freedesktop.Platform.GL.nvidia-530-41-03                                   1.4                    flathub            system
nvidia-535-54-03                                        org.freedesktop.Platform.GL.nvidia-535-54-03                                   1.4                    flathub            system
Intel                                                   org.freedesktop.Platform.VAAPI.Intel                                           21.08                  flathub            system
Intel                                                   org.freedesktop.Platform.VAAPI.Intel                                           22.08                  flathub            system
openh264                                                org.freedesktop.Platform.openh264                        2.1.0                 2.0                    flathub            system
openh264                                                org.freedesktop.Platform.openh264                        2.1.0                 2.2.0                  flathub            system
Freedesktop SDK                                         org.freedesktop.Sdk                                      22.08.12.1            22.08                  flathub            system
GNOME Application Platform version 43                   org.gnome.Platform                                                             43                     flathub            system
GNOME Software Development Kit version 3.28             org.gnome.Sdk                                                                  3.28                   gnome              system
Mint-Y Gtk Theme                                        org.gtk.Gtk3theme.Mint-Y                                                       3.22                   flathub            system
Mint-Y-Aqua Gtk Theme                                   org.gtk.Gtk3theme.Mint-Y-Aqua                                                  3.22                   flathub            system
Mint-Y-Dark-Purple Gtk Theme                            org.gtk.Gtk3theme.Mint-Y-Dark-Purple                                           3.22                   flathub            system
TigerVNC Viewer                                         org.tigervnc.vncviewer                                   1.13.0                stable                 flathub            system

--- When trying to update, it tells me that 3 Flatpaks have likely been moved out of the GNOME repository

$ flatpak update

Looking for updates…
F: Warning: Treating remote fetch error as non-fatal since runtime/org.gnome.Sdk/x86_64/3.28 is already installed: No such ref 'runtime/org.gnome.Sdk/x86_64/3.28' in remote gnome
F: Warning: Treating remote fetch error as non-fatal since runtime/org.gnome.Sdk.Locale/x86_64/3.28 is already installed: No such ref 'runtime/org.gnome.Sdk.Locale/x86_64/3.28' in remote gnome
F: Warning: Treating remote fetch error as non-fatal since runtime/org.freedesktop.Platform.GL.default/x86_64/1.6 is already installed: No such ref 'runtime/org.freedesktop.Platform.GL.default/x86_64/1.6' in remote gnome
Nothing to do.