I think that was your first mistake, it was the same with Genshin & HSR. You realistically should only want one character at the current threshold on each team. Supports can stay 10 levels behind. Focus on echo EXP would be my recommendation.

I wouldnt take it too hard, up until this point it was still excusable to make such mistakes: It's not until very recently the whales broke through union level 60 only to find that the daily training portals dont get better rewards after that. And honestly, for the skill level materials, it wasnt worth farming them at lower union levels due to lower drop rates. Also, the whole echo rolling thing is so timegated and RNG, so it's forgivable for thinking that it can be left aside for now. Yes, it might be the difference being able to clear the whole Tower of Adversity, but assuming we arent whales and pro players, it's fine. We are not rich or skilled enough to be able to beat lvl 90-100 challenges at a natural disadvantage.

dont try to get all your character to max level, or even max weapon level. haing them 1 stage lower is ferfectly fine for regular content. unless you want to push tower ot hologram, dont try to push your character to max. that is a trap gacha game put you into so that you ran out of resource faster

This is what ive been saying about this game since day 1 this game value its game like genshin. All the rewards and asterite we got because of events and compensation which are not valid in the long run. The main game gives us with basically lower than bare minimum. 10 asterites for a puzzle? In a 1600 multi pull? This isnt enough at all. It sad that no one speak out about this because in the long run this game will be like genshin. We dont even have end game aside TOA rn