This is part of the problem. If you don’t run a mining node, it IS for others to decide. Transactions don’t just appear in a block, a miner, not a hasher, decides which transactions they use to construct their block. There are currently over 200,000 transactions in the mempool.com mempool and FOUR nodes (over simplification, I suppose, but essentially accurate) WILL decide which ~2500 of those + 200,000 to add.
Assuming they will always simply add the highest tx with the highest fee is an assumption that has already been proving wrong by Luxor.