The category $\mathrm{Locale}$  is equivalent to the category $0\text{-}\mathrm{Topos}$ .
The 2-category $\mathrm{LocalicGroupoid}$ (with suitable localization) is equivalent to the 2-category $1\text{-}\mathrm{Topos}$.

> Is it true that the $\infty$-category of sheaves on a simplicial locale defines a complete embedding $\mathrm{Sh}: \mathrm{Localic}\infty\text{-}\mathrm{Groupoid} \to \infty\text{-}\mathrm{Topos}$ (where the first $\infty$-category, I expect, can be defined as $[\Delta^{op} , \mathrm{Locale}]$ with a suitable model structure).

If so, how is his image characterized? Maybe these are the $\infty$-topoi that can be obtained by topological localizations?

This looks extremely natural, but I could not find where this is discussed in the literature. I found only the following relevant pages:
 * https://ncatlab.org/nlab/show/classifying+topos+of+a+localic+groupoid
 * https://ncatlab.org/nlab/show/sheaves+on+a+simplicial+topological+space

I also found a very similar thread 11 years ago: https://mathoverflow.net/questions/93517/infty-topos-and-localic-infty-groupoids. But it seems that I have a slightly different accent and in any case, what has become known since then?