I have built myself a expense tracking tool, where I track my expenses. I have one "account" for my expenses and another shared one that I use together with my girlfriend.
I input expenses manually and each expense has a "category". For each category I can set a monthly "Bucket" (the maximum I wanna spent) and then I can track my progress during month.
Every month I get email with spending stats and I sit down together with my girlfriend to consider our finacial situation. We can change the buckets, etc...
I think the most inportant part is manually writing expenses and then talking about it after we get the email.
I also sync my notes, contacts and other stuff via Nextcloud, as I don't wanna use Google.