This strategy won’t work. As a frontrunner, typically what you do is reconstruct the pending block form the mempool. Or maybe an expanded pending block, with higher block size. But the idea is that you have a pretty good idea what’s likely to get mined in the next few blocks.
You’re not going to target a transaction until it’s about to be mined. A transaction with low gas won’t get frontrun until if/when it’s at the top of the mempool gas queue.