It doesn't matter

Your Western accent will sound different from that of native speakers of Hebrew. You may never sound like Israelis. Don't let that bother you.

People abroad often laugh at those who speak with an accent. Foreigners are sometimes ashamed or embarrassed about the way that they speak. On the other hand, new immigrants in most countries usually expect local people to accept their different language abilities. They develop their inhibitions later on.

Israel is different. Israel has always embraced olim. There are many more people who don't speak Hebrew perfectly than those who do. You're in good company!

So many Israelis speak with an accent that nobody laughs at those from other countries - except for some general ethnic jokes and blunt Israeli teasing.

Their occasional teasing about that impossible "R" that doesn't turn into a Hebrew Resh will not be held against you.

Don't be self-conscious. Don't worry about your vocabulary, your grammar, or your use of the Hebrew language.

Summary

There are many considerations to keep in mind when coming to Israel. Your accent should not be one of them.

Before long, you may even start to correct others' Hebrew. Then you'll be the one who is annoying others.