I'm stuck on annoying levels every now and then too, and patience really is the key. What works is playing slowly, not rushing - gives you time to spot the combos that matter and not waste your moves for nothing. On your Xiaomi it should run smooth, so it's not a technical issue. Try focusing on making cascades, those moves that chain into each other, because that gives way more points than just clearing the board.
Another trick is taking advantage of the free boosters the game offers - they usually give you some extra lives now and then, or boosters before the level starts. Play when you're rested, because being tired leads to bad decisions. And honestly, sometimes the best move is just to leave it alone for a few days and come back with a fresh head. The levels don't get easier, but you get mentally better at solving them. A lot of people get past those brutal ones just by waiting for the right moment, without spending anything.