Genshin is very hard optimized on using the right team-combinations. To the point that it becomes impossible to solve tasks if you don't have the matching elements for it. But of course this only comes into play on later levels, when people have become addicted.
While this is true they also give you a character of every element (anemo, pyro, cyro, hydro, electro, and geo) for free so you aren’t actually locked out of any of the content or puzzles. In fact there is a famous Genshin YouTuber bwaap who has completed the game using only the 4 starter characters to prove that you can. It’s not the easiest task but it also isn’t super hard, especially since some of the free units they give you are comparable to the top tier 5 stars you can wish for. In fact one of the strongest teams in the game is made up of only 4 stars which are really easy to get since the rate for them is much higher than 5 stars.
