Tours from San Pedro de Atacama to Uyuni Salt Flats

Traveling to Chile next month and would like to hear your personal experiences with the San Pedro de Atacama to Uyuni Salt Flats tours.

Seems like most tours are done via 4x4s with contracted drivers over 4 days/3 nights in remote areas without cell service or nearby cities. I also can’t tell if there is any difference btw the tour companies, but it seems like this is something I’d book upon arriving to SPDA. Is there a particular tour that you would recommend? How did you fit the tour into your overall Atacama trip?

In addition, as a solo female traveler, I am first concerned about safety and privacy, especially in a situation where I would not be able to call for help… can anyone share their experiences? Anything of note? Did you encounter other solo travelers? I would pay premium for peace of mind, although I have not seen any lux option. I am still on the fence but cannot imagine going all the way to Atacama and not seeing the Uyuni salt flats…