What camera gear to take? (EBC)

I have just booked a trip to Everest Base Camp (Longer Gokyo Lakes circuit) and my mind is already turning to what camera gear to take.

The closest I have done to a trip like this was Peru, I did not do the Inca trail but a slightly higher hike which topped out at 4600m, so not far off from what faces me but this was shorter and probably not as cold as what I will see, although tea houses will likely be slightly warmer than a tent at 4500m! Along with my phone (iPhone 13 pro max at the time) I took a Canon G1 X mkiii and it was great, good image quality, good focal length and was easy to carry. My rationale at the time was that I wanted to get great photos but that the purpose of the trip was hiking not photography, so I was not likely to get proper time for photos other than at breaks or the end of the day at camp. This proved to be bang on.

I currently own:

Panasonic S5 with 16-35 and 50mm 1.8 Fuji X100f No longer own the Canon, sold that long ago which I have regretted many times since!

I am not sure either are totally ideal. I'd be happy taking the S5 but I sense that whilst the 16-35 would be terrific I will likely need something longer too and I am not keen on changing lenses in the kind of environments I am expecting so a one lens solution I think is best. Picking up the 24-105 or the Sigma 28-70 for the S5 is an option if I did want to take the S5, the 24-105 is a beast though.

The X100f would probably be terrific as a walkaround at places like Namche but likely too restrictive a focal length overall, I could add the 2 converter lenses to give it more versatility I guess.

This is a once in a lifetime thing so am happy to buy something new, if that is really the best thing, currently mulling it over.

Thoughts and experiences appreciated.

Thanks