Other issue

[ramagosumt]

I have some other issues also if that can help you address the other ones:

1. The Tray Scalar didn't really optimize: it collapsed with the File Explorer although there is still space beneath it. I'm using 16:9 (2560x1440) btw.
2. The adaptive Tray App rewire looked not like how it was in the Steam guide.

[Xenon257R]

This does help a bit. To go into detail:

1. The File Explorer initial setup probably didn't calculate accurately where it should've been positioned during initial startup for larger resolutions like yours. This is easily fixable on your end; simply open its context menu, click on Manage App and change its X and Y positions in the Rainmeter client to a better position.
2. Some graphical elements are not rendering correctly - again, as you have correctly guessed, this is a scaling issue; I probably did not write in multipliers correctly and the magnification is off. I will fix it in a future patch.

Both of these reports are very helpful, but unfortunately does not help address #9. I will close this for now, leaving the answer:

I will make sure these graphics are corrected for non-1920x1080 resolutions in a future patch.

[Xenon257R]

As a temporary fix for the tray apps issue, open the BlueArchive\0_Settings\AppSettings\settings.inc config file and insert the following line of code right below the string @includeVariables=#ParentConfig#:

GScale=1

This will make it so the settings GUI will assume your monitor is 1920x1080, where the graphics are known to be correct. Of course, given your monitor size, this will make this UI very tiny, but everything will be aligned. This is only necessary if you wish to use the graphical wires to assign colors to your app instead of writing them directly in the .inc files for each app, so it is up to your preference.

[ramagosumt]

Okay, just so you know, after I added GScale=1, this appeared

Then I clicked Rewire App, and it had become much better, and the other thing also disappeared.