For all those who develop their own bots here are the main mistakes to avoid.
- Don't start your first transactions from a fixed fee.
- Don't increment a fixed amount.
To solve previous points you need to read what is the current fee in sat/vB and increment from that point, network only will accept transactions if those are +1 Sat/vB from previous know transactions.
Learn how to calculate your transaction size and set your fee multiplier this must done to try to maximize your possibilities to be accepted in mempool, without the need of burn all the fee.
What if the transactions have less or more inputs/outputs?
Let's say first TX has 900 bytes and some fee.
Would another transaction of 300 bytes, with less inputs, but a larger fee/byte, and so a smaller total fee, be accepted and replace the first TX?...
What if the first TX has input X among several inputs, and another TX only has X as input? What would the miners choose? It doesn't sound like an easy to solve problem.