I've build a tool to detect differences between _my local_ mempool and what miners include in their block (there will always be slight differences). This is primarily intended to detect censorship, but can also detect transactions that never entered _my_ mempool.
Brilliant! I remember thinking about this problem a few years back: what stops miners of a blockchain just ignoring transactions/anything from certain entities. So it's good that there exists a way to track such behaviour, if it is occurring.
Economics. If miners consistently ignore certain transactions, there is space for new miners to enter the market and earn super-normal profit. After the next difficulty adjustment cycle, the old, censoring miners may be priced out.
Yes! Will be on umbrel eventually. Currently needs a Bitcoin Core build from the master branch. The features use should be in the upcoming release. Then Umbrel!
See https://miningpool.observer