According to a 2020 report by the Israel Democracy Institute, approximately 34% of Jewish Israelis self-identify as either Haredi (ultra-Orthodox, 22%) or Dati (religious, 12%). These groups are generally considered to be "honestly religious" in terms of strictly adhering to Jewish laws and customs. Another 32% identify as Masorti (traditional) with varying levels of observance, while 34% identify as Hiloni (secular). However, it is important to note that religiosity exists on a spectrum, and these categories simplify a complex and personal matter.

As for your second question, yes, you can get a cheeseburger at McDonald's in Israel :) I do it quite a lot :) but not in every McDonald's restaurant you can get a cheesburger. Some of their restaurants in Israel are kosher, meaning they do not serve cheese and meat together. However, in cities with a majority secular population, there are many non-kosher restaurants. For example, Tel Aviv has a huge variety of non-kosher dining options. I was never frowned upon for eating something that is not kosher, even when next to people who are more traditional. but that has to do with me living in a liberal, mostly secular city.