Tsco, take a breath before trying to use any advice given here. Assess where you are in the game. Where in the map can you farm knowing you will win every time. Are you raiding and winning? Are you in a proper alliance?
Much of the advice addresses only part of your play. But, the team you build must function at all levels of play while being flexible enough to change both as competition gets tougher and new heroes get added to your roster.
For now, concentrate on farming first as this is the basic building block for both team and base. If you can beat province/level 7-4, you can fill your monster chest quickly. After that comes a raid team that can win three out of four attacks.
This gives you hero chests. Next is a team that can get through the 4th stage of rare quests which gets a 4* ascension material. LAST, is the alliance.
Most will tell you to join a teaching alliance. My opinion is this forum has enough old posts that should be read which can teach much more; so, find an existing four member alliance in which all members are alive and talking. You will get tier III loot with only 3% of total titan points. This grows you without feeling you are holding others back.
Your current roster has Belith who is important as both a healer and a debuffer. Colen is a good tank possibility and feww raiders will has a dispeller at your level. Oberon is not a great hero, but farming needs a good AOE hitter for clearing mobs early. It looks like you are one of us who fed Bane, so Melia is your yellow. And, while he does suck for many, Greymane is your blue hero until you get something better.
And, push a watchtower for resource growth. Do not worry about being raided.
Forgot…do not feed Lianna. Wilbur is way above Gormeck, but not at this level.