To me she does look very similar to some lines of Sars especially considering her age. I have had Sar enthusiasts tell me straight up they think the females are "ugly" in comparison to the males (on average of course) because they tend to have a thinner coat and lankier body. There are a few breeders of Sars here in North America, some reputable, some not so much.
Whoever adopts her needs to be warned that it is not uncommon for Sars to not "turn on" to their guarding instincts until at least 3-5 years old!!!!! It is very typical as puppies to be happy and goofy and want to be everyone's friend and then as they age they start to become more aloof and eventually territorial. With proper socialization they should always be good with invited guests. As long as you are happy, they are happy. With strange dogs however...well...Keep in mind they were bred specifically to run off any sort of predator-type in order to keep their flock safe so this would include anything from bears to wolves to stray dogs and humans with ill-intent.
I have seen an angry adult male Sar in person and it is quite the site to behold! I would definitely NOT want to be on the wrong end of that dog! The nice thing about Sars though is they typically give ample warning that you are pushing your limits too much with them before they take matters into their own...paws. The owner should learn to read their body language carefully in order to be able to predict the situation and remove their Sar before things escalate more than they need to.
Of course, this is if she even is indeed a Sar.
The illyrian shepherd looks very Sar-like but is slightly different. Also it would make sense that she looks kinda leonberger-ish because the Sar was used to create a leonberger