Three issues with my X-T3: related or independent?

Julesvernex2 wrote:

My Fuji X-T3 has, over the course of a month, developed three issues:

1. First, I started getting brief EVF/screen blackouts when zooming with a particular lens (the 70-300mm). Camera-lens contacts are clean and the lens works fine on other cameras
2. Shortly after, I started getting a "Turn off the camera and turn on again" when shooting with the mechanical shutter (initially only on portrait orientation, then on landscape as well)
3. Finally, the camera refused to turn on. I've taken out the battery and SD card, and regularly see if it comes back to life, so far with no luck

Can these three issues have the same root cause? They don't appear related, but it would be quite the coincidence to have three different problems pop up within one month, particularly in a camera that has so far worked flawlessly for 90,000+ shots.

Is there anything I can try to get the camera working again? Is it worthwhile to send it for repair?

Many thanks,

Just a guess, but any exposure to excess humidity, or have you been shooting near salt water? The progression of issues sounds a bit like possible moisture damage or corrosion. If it were me I'd at least pay the money to send it to Fuji repair for an estimate. However, I know how much used X-T3's are selling for locally, so if the cost for repair was too much I wouldn't do it. Disheartening I know, but these things aren't bullet proof

Edit: forgot to ask if the firmware on both camera and lens are up to date?