Not exactly "struggle", the word is a bit more complex and can't be translated exactly, the word is taken from the Arabic word "Juhd" and its verb is "jahada" which means "effort" or "put in effort", like if you want to say for example that a kid is studying hard you'd say "yujahid" which is a conjugation of the verb.

In the context of Islam, "Jihad fi Sabeel Allah" translates to putting effort for the way of Allah, which means helping Muslims, protecting them, or spreading Islam through the necessassary methods available, it also has to be declared by a trusted Islamic authority for good reasons and following Islamic war rules, so going to war with a neutral neighboring country for no reason doesn't count as Jihad but as a crime instead, obvious to say most of the so called "Jihad" groups aren't doing actual Jihad but the business of their U.S. funders... I am not sure of it but by the definitions I find online Muslim PFLP fighters could count as doing Jihad Idk.

As for why groups put "Jihad" in their name, they just want Muslims to join their organization or be on their side, because Islam has rewards for Jihad and etc..