You aren't that wrong, CoD on lower floors are pretty much normal matches, but sooner or later you will reach your limit of either survivability or time usage (45 min limit). Extra strategy is only there to move your limit a bit higher at cost of some real time and stress.

Lucid is said to be one of the best PvE strikers, so no need to change there. Especially with Lucid, using 2 active passers is quite a good idea, but that is provided you have enough spirit. Assists usually are good at generating it, but if you use forward pass, remember that you lose some for that. In your case, Luka and Sillia should be very good. In mid, place some forward passers, top choices are Limnay/Leonard (spirit generator) and Rosalia (penetration power), but Sammy should do good too. The reason is to save your precious time - you won't need to tip away those thousands of HP again. You could place extra stealers (Magnus), speed totems (Magnus, Cynthia, Kevin) and spirit generators in mid too.Tip. place spirit generators or any leader types to the right, forward passers in the mid and stealers to the left, if they all have max action bar, they move from right to left. In the back, opponent attacks a lot with cheated speed, but their damage is low and rarely crit except for strikers, so Kei would be great choice. Use him to penetrate, that keeps the ball on him, takes time but is really effective. Except for that, you just need to heal, heal and heal. Best combo for healing is a Coexistence player (i.e. 4* Mimi or Sirius), Healer like Avnore and a Kevin. On later floors, you need to take more notice of time, so Mariel is a real saviour providing that you have enough tankiness/healing. Also don't be afraid to use active heal, you'll have enough spirit by passing around in the back, but the main reason is to progress you action bar to safely forward pass from mid to front and then steal after shooting in the front without getting interfered with enemy actions.