jerryy

After digging through the manual, I found this happens when the compression type is set to All-Intra with the 4K frame size. Whether or not this also occurs when Long-GOP compression, the manual does not say.
Do you have a way to read the exif information from the movie file?

I searched for your issue in other forums and few had it and they said it's after the latest firmware version etc... And they said this.  "when choosing movie compression Long GOP only show this message, otherwise if choosing all-intra it will not show the message" . So i hope this helps !.. i'm youta, not k . Have a nice day !. [Also if you don't have HDMI 2.0 you won't be able to record 4k60 , so check your cable too , HDMI 1.4 can only support 4k30]

Ha! You beat me to it!!!!!

Something minimal...

Picture quality is very high. Fujifilm camera pictures has high quality.

open thread.

After the sky cried and the tears flowed down the street ... (1)

(1) lyric from various songs.

There is DarkTable : http://darktable.org
and Fujifilm Raw Converter: https://fujifilm-x.com/en-us/products/software/raw-file-converter-ex-powered-by-silkypix/
Both of these are free and very worthwhile.
It seems strange to process jpegs other than to resize them. It certainly can be done with decent results if you saved the original in-camera at 100% quality and only edit them once; never edit - save as jpeg, reopen, edit -save as jpeg, and so on because the lossy format will degrade the image so much the image gets ugly. Perhaps it is better to tune your in-camera settings to give you the desired outcome. The raw converters will let you experiment with various choices and not damage the original.
Since Fujifilm released X Raw Studio, capturing raw + jpg is not as needed since one can now just connect the camera to the computer and use X Raw Studio if there is a need for the camera made jpg version, which in turn, saves space on the camera card while shooting.

(American) five-lined skink (Plestiodon fasciatus) or blue-tailed skink (for juveniles)

https://www.filmriot.com/blog/frame-rates-vs-shutter-speed/
It sounds like you have tried to set the shutter speed lower than 1/60, which is a problem for X-T3s in movie mode.
I do not use the Ninja V, so I cannot answer your second question.

After the sky cried and the tears flowed down the street ... (1)

(1) lyric from various songs.

Lake Garda, X-T3, XC 15-50mm

Excellent @jerryy I can now get the camera to zoom in when I press the focus lever. I don't think I would have ever found that out from the manual so many thanks indeed. I had tried every other function button setting except this one 😀

https://fujifilm-dsc.com/en-int/manual/x-s10/menu_setup/button-dial_setting/#focus_lever_setting
Did you try turning the Focus Lever menu setting to Zoom mode and then try to zoom?

It might not hurt to update the firmware(s) the current body version is 1.40 and the lens is up to version 3.23. There were some bugs that got squished by the updates.
https://fujifilm-x.com/global/support/download/firmware/cameras/

https://fujifilm-dsc.com/en-int/manual/x-s10/menu_setup/button-dial_setting/#focus_lever_setting
Did you try turning the Focus Lever menu setting to Zoom mode and then try to zoom?