How to clear high-difficulty content with a limited number of characters

I can't invest too many resources into training, so I need to pinpoint who to focus on. A main attacker and a character who can also serve as a support/sub-attacker are essential, and there aren't many new 4-star characters either~ 🤔 I really want to get who I'm aiming for, but the character I want is coming in the gacha after next, so I'll have to try and pull a good 4-star from the permanent weapon banner 😇 Does anyone know of any good strategy sites? It's more active than other gacha games, but to delve deeper than strategy sites, YouTube is the way to go. I used to binge-watch YouTube when I was grinding Granblue Fantasy and Genshin Impact too.