How to get 5 star characters?

So I started Genshin around a month and a half ago, and am currently doing on some world quests that I left half finished (I started it thinking it was short but realized they were LONG) and was wondering that the gacha wish thing was the only way to get 5 star heroes?

I have a bunch of 4 star characters from the pulls but only have Keqing as one of the free characters that I got in the beginning.

I’m starting Inazuma and heard it was a short chapter so I’ll be probably be finished in a week or less depending on how much free time I have. I just want some strong characters to level up. I heard there are quests sometimes where you can get characters for free but I’m not sure if it’s only for 4 stars or it also reaches to 5 star characters.