Kudos to @Coppersky for bringing up the importance of a thread like this. I run a decent team that with patience, got me above 3100 trophies and into the top 10 (this did not last long, hahahaha). But province 21 hands my butt to me with this team.
I tend to run a very different team for high level provinces.
This is FAR easier to run provinces with, despite being 150 team power lower. Don’t rush to use your specials, bring antidotes, bring potions for the odd chance you get stuck with no heals coming in, and you CAN do this with lower quality heroes.
Heroes like Kailani 3* can be critical, as typically, spike damage (large damage to one player) is what will hurt you the worst. Try to pick heroes that work with each other in terms of good synergy. IE, someone that debuffs the opposing team, like Ulmer 3* and someone that gives you an attack buff.
All of us tend to run into hard spots where we feel like we can’t progress well, and for that I recommend the following: don’t give up, raise new heroes on the side to have a varied team! It can feel rewarding and fun to farm lower levels while building up heroes on the side to help you progress further! You may even find a new play style you love! (double healer, riposte, 5 attackers, etc)