I run mono teams. I’ll pick the biggest SOB on the battle field and punch him right in the nose with my strong team against his tank. Then I move to the next biggest guy and stack against the flank and work my way down untill I’m at my last flag with scrubs. I’m confident hitting 4300 to 4400 defence teams with the scrub team which is just the 4* heros I’ve replaced with 5*'s on my goto teams.
I used to hate wars, untill I quit caring about my score. Now I go into war with the mindset if just busting a hole in the big defence teams so the cleaners can do their work, but I’m usually good for at least 4 one-shot kills. Note, 4 one-shot kills on defence teams stronger then your defence team will cover the points lost by your defence getting killed 4 times. Your last two flags are used to help the lower level players cover their lost points.
You have to use raids to find your sweet spot on the defence teams you can be effective on. Drop trophies, and work your way back up to the level your at now. You will notice a spot where the weaker defence teams actually give you trouble. Make a mental note and always hit ABOVE that spot.
Mono attack teams can easily take defence teams that 400tp stronger(300tp to 500tp stronger is my sweet spot). I’ve even one shot teams that were 1000tp stronger then my attack team, but don’t recommend doing that unless the leader gives you the thumbs up.