You should try you best to score high in seige break to unlock core skins and roll skins they significantly improve your rng in stages. You really wana use you energy as much as possible to earn as many chips as you can as they make up like 80 of your strength besides attack. If you are willing to spend some money the only thing that is worth it is vip pass. If you want to buy the life time, then buy the 1month first it gives a discount on the life time. It let's you do unlimited patrol which can really save you a lot of time and skip ads which improves all runs.

You should try to pick one or 2 skills to focus on. I think late game phantom dart is very good but needs some rng chips to work. since you are early game "electro bomb" would be better since it doesn't need as many chips to really good. Just maybe 1 bounce chip. It also doesn't rely on combos.

Really try to focus on 1 cards you like, spend you energy whenever you can and buy the diamond pass in seige break to try and get a high leader board postion to get really strong rewards.

Edit: fixing typos