I have two primary databases.
I really, really like to keep my work and personal things separate. I have a work laptop and I don’t want any personal information on it for more than a day. I use the Global Inbox 99% of the time when adding something to DT. If I’m working and think “Oh, here’s a thought that I want to capture for my personal database!” I’ll write it in the Global Inbox and then after I sync I can just move it to where it needs to go in my personal database on my phone. On my phone I sync both databases.
I create a new database every year for my work and personal databases (unimaginatively titled “Work 2024”) so that things don’t get too wild.
Oh, and I only use Bonjour because it’s fast as hell and gives so many less errors than anything else, in my experience. Also, as far as I’m aware, it’s one of the most secure options since none of you data sits on any servers.