applications not listed in 'show application'

I have re-installed my Ubuntu 22.04 LTS after struggling with some issues.

• My original installation was Ubuntu 20 (I believe 20.04), which got updated to 22.04 before this re-installation attempt.
• My /home is in a separate device.
• I have a 2nd (3rd considering we have also the boot) partition in the same device where the Ubuntu system is installed.

When I was re-installing it, if I got correctly, the selection I chose was to not erase/format the partition, but replace the system files. The swap file is kept as I have before at the root, in the same size, for example.

Since then, I am struggling with applications being installed but not listed in 'show applications'.

• I see several other topics asking about specific application icon being not available at 'show application' (like this).
• I know we must generate our own .desktop files to have it available on the desktop or application list for cases like: appImages (and Anaconda navigator most recently, apparently).

I am struggled with the following:

• My 'show application' screen is almost empty;
• I have already installed Chrome after the re installation, I can find it if I search for it, but it is not listed.
• the /usr/share/applications folder have a lot of .desktop files, most of them not shown in 'show application' screen.
• I found a chrome's .desktop file in /usr/share/applications folder. and I attempted to add a .desktop in .local/share/applications as found in several discussions as being the reference for 'show application, with no success;

So my questions are:

• Where must I put the .desktop icons to effectively have the applications listed? I want to have it listed to add as my 'favorites'.
• Considering the two folders differences and none of them being reflected in 'show application' list, it sounds like I messed up here in some configuration. How can I correct it? Or if I attempt to re-install Ubuntu how must I do it in order to not have this issue again?

Update:

I realized something I believe can be relevant: When I made the re-installation, the home device got unmounted, and a full /home directory was generated. I am starting to believe the problem is related to it.

1. I mounted the device using the Ubuntu's disk application.

2. I re-mounted the device in /home, even with other folders there… just ignoring.

3. After mounting + restart, I saw my desktop icons back. So I was happy thinking it has worked...

4. But I am starting to think it has not worked so well... the apps not being listed I believe is an evidence of it.

5. Originally, I had an alternative user also in that device (before reinstall).

6. But after mounted, I see just my user in /home.

7. I see the 2nd one just when I access the device directly (not through /home).

8. I am unable to see any of the newly created /home files…

9. I suppose the Ubuntu is listing the ‘applications’ from .desktop files automatically generated in the newly created /home folder…

So my questions now are:

• Is my problem described here because I mounted my home device at /home directly?
• how to make Ubuntu list all applications?
• Considering the above, I believe I made something wrong in the re-install… Is it possible to set the Ubuntu must use that home device?
• How I should be done it in the order to have my ‘home device’ promptly mounted as /home (instead of creating new one)?
• How is the correct way to mount a ‘home device’ when Ubuntu has already a /home folder?

Update2 - apparently the problem is not two home related

I reinstalled again Ubuntu 22.04 LTS as described here, making sure:

• the system partition is formatted (but others of that device is kept untouched).

• to have home device mounted correctly on /home;

• And I suppose no new /home beyond the used to mount the home device.

But I have still the same situation... So, it is not because I mounted a home device at /home after the installation created the all new home folder.

The output for printenv XDG_DATA_DIRS asked by @vanadium in the comments continues the same:

/usr/share/ubuntu:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop

I have checked the output paths, specifically the corresponding "applications" folder inside them, when it is present. No one appear to reflect the applications listed... Would be the idea to copy-paste the corresponding .desktop files there? in "applications" inside them?

I am sorry if I am using the wrong terms. I am not an advanced user.

Any help is really appreciated.