I used to keep notebooks like that (without the index cards) but now stick with Evernote with some Google Docs use. My life is in Evernote. My phone app is fingerprint protected, and I keep it otherwise protected with a strong password.
After a few years of Evernote use, I started paying for the Premium version so that I’d have access to every note, everywhere. I save bookmarks in there, as well as scraps for ideas.
I use Google Docs & Sheets for content calendars (spreadsheet — colour-coded to indicate whether I’ve completed a draft, whether the article is finished & scheduled, or in progress), to track article ideas (including links to articles or podcasts that inspired the article/post so that I can easily refer back to the source material), and for article notes.
I keep article notes in both Google and Evernote, which does occasionally get confusing. My spreadsheet of ideas has a drop-down column where I tell myself whether I’ve put the accompanying notes in Google Docs or Evernote.
I like the searchability of doing it all online, being able to copy and paste, and being able to click on links. Plus, I have terrible handwriting. I’m in awe of your penmanship.
The best system is the one that works for each person. (And I realize that I’m not saying anything revolutionary there. I don’t expect anyone to disagree. :) )