Update: Here's the "Why not Lemmy" bit from my post above:
Lemmy is like Reddit but decentralised and run on a non-profit basis by many collaborators. This is great, and a much better fit, but it has problems of its own: it doesn’t work with my main browser Safari, the RSS feed is difficult to announce in chat, it is technically complex and immature, and it is not sufficiently different from Reddit to motivate reddit users to move there. I’m grateful it exists but at present I find it underwhelming for our needs.
Because of this, and positive early response to the experiment (including from the Reddit and Lemmy mods), and my personal readiness to try a more featureful setup, I'll keep going with this. I invite you all to visit, join, and/or cross-post there to get more eyeballs and answers:
Disjoint date periods in a single report are not well supported by most accounting software, see recent hledger issue. Nice solution!