IIUC this post will be shown on the Open Source stage at Bitcoin 2026 so people can zap me during our panel.

If your answer is an address index that also seems a bit underwhelming; BTCDrak already released such a Bitcoin Core fork over a decade ago but I guess no one really cared: https://bitcoinmagazine.com/technical/bitcoin-rbf-bitcoin-knots-and-bitcoin-addrindex-three-core-forks-that-don-t-break-with-consensus-1458237046

Do you have an answer to this question?