Nice domain and nice concept. I too am among those with a home-grown approach to managing the budget. Mine is more of a spending journal than it is about planning or reconciling the entire budget, with motivations similar to those who would have a meal journal. I focus on the decision making process and self-evaluate spending according to my budget and my overall values.

My approach won't appeal to a lot of folks, but there are dozens of us who find it super useful: https://www.spendlight.com/#how-it-works

We're on the same page regarding privacy. Except for taking money for the subscription, I keep my hands off bank accounts. And for those wanting a complete air gap, there's always the printable paper version: https://www.spendlight.com/download/paper-spending-journal