It seems that the biggest issue that is plaguing MV, only amplified on Android, is that the JavaScript interpreter is single-threaded. Modern devices, both desktop and mobile, have multiple processor cores to handle concurrent processing. Most modern games try to take advantage of this and offload various processing tasks to multiple threads/cores. This isn't possible on MV, so you're dependent on one CPU core, which means you're limited to the clock-speed of your processor.
MV has to do everything for an entire frame within that clock speed. On a desktop PC, there's extra room for more graphics, events, plugins, effects, etc. But on mobile, you'll be using up the entire CPU. This isn't even mentioning that there are a lot of scripts not written with Canvas compatibility in mind.
Given how complicated the game can become with regards to equipment and passive effects, it's probably a little too intensive for phones. The RPGMaker engine itself isn't very stable or optimised, having previously had memory leaks. After a lot of tinkering and fixing, the game is in the most optimized state it's ever been in. It lags significantly less than it used to. However, I really recommend against playing this on mobile phones. It only exists because people would beg me for it if it didn't. It completely lacks music, which I'd argue is core to the game, and is most likely to have hardware issues.
This is already a lost battle and no amount of googling or troubleshooting will help me find a solution. The only option would be to make a different game, optimized to hell and back, that doesn't feature tons of scripts and passive effects.