I've encountered this same problem, also on an X-E4. I hadn't had any problems with the camera, I just wanted to test the procedure. Some points:
- I use a PC running Windows
- The version of Acquire is the latest.
- I also own an X-S10 and backup and restore worked fine with that, and I'm using the same cable, etc.
This is just a guess, but the specifications for that monitor say it only supports 8-bit bit-depth. Most of the video outputs for the X-T3 are set to support 10-bit bit-depth.
Try using the H.264 codecs, with the same frame rates, etc. and see if you get an image.
H.264: SD card, 4∶2∶0, 8-bit/HDMI output, 4∶2∶2, 10-bit
edit, edit: Welcome to the forum.
Last time I powered on the camera, I noticed that when in aperture priority the display of shutter speed disappears. Same if I go to speed priority, the F display disappears. Until last time I used the camera everything was fine. They now both only appear when in manual. I went through every possible menu but could not solve the problem. any help? Thank you.