https://github.com/actualbudget/actual
It's software for budgeting. You can run it entirely local, or set it up as a server. It stores everything in an SQLite dB, let's you import and export CSV files, and it gives you great options for querying and seeing reports on your financial records.
I've got a handful of accounts, so I set up a small python utility to parse the CSVs my banks give me to something actually sensible and readable for Actual. I do that once a month, add a reconciliation entry here and there, and it's all kept on sync very well.
I have one morbid report titled "money pissed down the landlord drain", and it's far higher than I'd like to be. But it's got close to every penny I've ever spent on that bullshit in one place.