SrMi

The second focusing frame (not visible in MF), is enabled by AF/MF Setting > Corrected AF Frame > On. There is a reason why that is recommended setting. Here is one article discussing it: https://www.jmpeltier.com/what-is-corrected-af-frame/

The simplest way to enable back button focusing is to switch to the M-Focus mode (slider on the left) and use AEL/AFL button to trigger focusing. Let me know, if that is not good enough for you, and I can show your other relevant settings.

Do you hear the camera's mechanical noises? You can switch to the electronic shutter to eliminate the shutter noise. Closing the aperture to the working value also produces noise. The only way to eliminate that noise is to set the working aperture to the maximum value (f/2.0).

The noise is mainly determined by the exposure (shutter speed and aperture), not by ISO. That is why some do not see much noise at ISO 3200, and some do. With any camera, to minimize the noise, you want to open the aperture and slow down shutter speed as it fits your creative constraints (DOF, object movement, camera shake).

You need to find a charger that can provide 5V, 3A (15W) in order to charge as fast as with AC-5VJ. (Charger specs are here: http://fujifilm-dsc.com/en/manual/x-t4/technical_notes/spec/index.html)

Image Capture transfers image from SD card to your computer. What do you use to view the image (where you see the black bar)?

What kind of raw converter are you using? The black bar on the right side indicates that the software you use does not support X-T4.

A blinking red icon means that the current GPS location was NOT acquired. Instead, the last known GPS location (your home) is being written into image EXIF data. You must wait until the blinking red icon becomes white, then you will have correct GPS location. Yes, it works when GPS icon is white.

I don't shoot video. I like the stills/video switch as the menu is not "polluted" with unnecessary video settings. Many cameras have the issue that you can accidentally start the video. On those, I disable the 'easy' video start if possible, but a switch like on X-T4 is preferable. Coming from X-H1, I like X-T4. Not sure about the new flip screen. Currently, I use it in a similar way as the X-Pro3 is designed: reverse for regular shooting, and flip on the side when I want to see the image in LCD or access the menu.

I have not heard about any plans. Fuji is apparently planning it for GFX100. IMO, it is not a very useful feature. I have several cameras with pixel shift and have never used it but for testing it.

What you are probably thinking of is animal eye detection. Fuji has not announced anything. I do not see why Fuji could not add it.

If you unscrew the left part then it is not an L-Bracket any longer, right? Can the LCD articulate when you only shift the left part outwards? RRS has announced an L bracket for X-T4, but there are no details available yet.

Are you thinking of FUJIFILM EC-XT M Eyecup for GFX 50S, X-T2, and X-T1? Thanks!

AF-C focuses at working aperture. Have you tried using AF-C with a wide aperture?

Fujirumors has published a slide (2/26) listing the measured number of stabilization stops for each lens when used with X-T4 (and X-H1). 18-55 is listed to have 6.5 stops of stabilization when used with T4's IBIS vs 4 stops when using OIS alone. As expected, IBIS seems to help.

Like on many other cameras, IBIS and OIS seem to be coupled: they are either both on or off. For 18-55, Fuji lists 4 stops of stabilization on cameras without IBIS and 6.5 stops when using it on X-T4.

You need proper USB-C to USB-C charging cable and a powerbrick at least like Fuji's AC-5VJ (rated output 5.0V 3.0A 15.0W) in order to use fast charging with the dual charger.